CWE-36: Absolute Path Traversal

Successful exploitation of this vulnerability could allow an attacker to read from the Experion controllers or SMSC S300. This exploit could be used to read files from the controller that may expose limited information from the device.

CWE-749: Exposed Dangerous Method or Function

Successful exploitation of this vulnerability could allow an attacker to modify files on Experion controllers or SMSC S300. This exploit could be used to write a file that may result in unexpected behavior based on configuration changes or updating of files that could result in subsequent execution of a malicious application if triggered.

We at IncludeSec sometimes have the need to develop fuzzing harnesses for our clients as part of our security assessment and pentesting work. Using fuzzing in an assessment methodology can uncover vulnerabilities in modern and complex software during security assessments by providing a faster way to submit highly structured inputs to the applications. This technique is usually applied when a more comprehensive effort beyond manual and traditional automated testing are requested by our clients to provide an additional analysis to uncover more esoteric vulnerabilities.

Introduction

Coverage-guided fuzzing is a useful capability in advanced fuzzers (AFL, libFuzzer, Fuzzilli, and others). This capability permits the fuzzer to acknowledge if an input can discover new edges or branches in the binary execution paths. An edge links two branches in a control flow graph (CFG). For instance, if a logical condition involves an if-else statement, there would be two edges, one for the if and the other for the else statement. It is a significant part of the fuzzing process, helping determine if the target program’s executable code is effectively covered by the fuzzer.

A guided fuzzing process usually utilizes a coverage-guided fuzzing (CGF) technique, employing very basic instrumentation to collect data needed to identify if a new edge or coverage block is hit during the execution of a fuzz test case. The instrumentation is code added during the compilation process, utilized for a number of reasons, including software debugging which is how we will use it in this post.

However, CGF instrumentation techniques can be extended, such as by adding new metrics, as demonstrated in this paper [1], where the authors consider not only the edge count but when there is a security impact too. Generally, extending instrumentation is useful to retrieve more information from the target programs.

In this post, we modify the Fuzzilli patch for the software JerryScript. JerryScript has a known and publicly available vulnerability/exploit, that we can use to show how extending Fuzzilli’s instrumentation could be helpful for more easily identifying vulnerabilities and providing more useful feedback to the fuzzer for further testing. Our aim is to demonstrate how we can modify the instrumentation and extract useful data for the fuzzing process.

[1] (Not All Coverage Measurements Are Equal: Fuzzing by Coverage Accounting for Input Prioritization – NDSS Symposium (ndss-symposium.org)

Fuzzing

Fuzzing is the process of submitting random inputs to trigger an unexpected behavior from the application. In recent approaches, the fuzzers consider various aspects of the target application for generating inputs, including the seeds – sources for generating the inputs. Since modern software has complex structures, we can not reach satisfactory results using simple inputs. In other words, by not affecting most of the target program it will be difficult to discover new vulnerabilities.

The diagram below shows an essential structure for a fuzzer with mutation strategy and code coverage capability.

1. Seeds are selected;
2. The mutation process takes the seeds to originate inputs for the execution;
3. The execution happens;
4. A vulnerability can occur or;
5. The input hits a new edge in the target application; the fuzzer keeps mutating the same seed or; 
6. The input does not hit new edges, and the fuzzer selects a new seed for mutation.

The code coverage is helpful to identify if the input can reach different parts of the target program by pointing to the fuzzer that a new edge or block was found during the execution.

CLANG

Clang [Clang]  is a compiler for the C, C++, Objective-C, and Objective-C++ programming languages. It is part of the LLVM project and offers advantages over traditional compilers like GCC (GNU Compiler Collection), including more expressive diagnostics, faster compilation times, and extensive analysis support. 

One significant tool within the Clang compiler is the sanitizer. Sanitizers are security libraries or tools that can detect bugs and vulnerabilities automatically by instrumenting the code. The compiler checks the compiled code for security implications when the sanitizer is enabled.

There are a few types of sanitizers in this context:

• AddressSanitizer (ASAN): This tool detects memory errors, including vulnerabilities like buffer overflows, use-after-free, double-free, and memory leaks.

• UndefinedBehaviorSanitizer (UBSAN): Identifies undefined behavior in C/C++ code such as integer overflow, division by zero, null pointer dereferences, and others.

• MemorySanitizer (MSAN): Detected uninitialized memory reads in C/C++ programs that can lead to unpredictable behavior.

• ThreadSanitizer (TSAN): Detects uninitialized data races and deadlocks in multithreads C/C++ applications.

• LeakSanitizer (LSAN): This sanitizer is integrated with AddressSanitizer and helps detect memory leaks, ensuring that all allocated memory is being freed. 

The LLVM documentation (SanitizerCoverage — Clang 19.0.0git documentation (llvm.org)) provides a few examples of what to do with the tool. The shell snippet below shows the command line for the compilation using the ASAN option to trace the program counter.

$ clang -o targetprogram -g -fsanitize=address -fsanitize-coverage=trace-pc-guard targetprogram.c

From clang documentation:

“LLVM has a simple code coverage instrumentation built in (SanitizerCoverage). It inserts calls to user-defined functions on function-, basic-block-, and edge- levels. Default implementations of those callbacks are provided and implement simple coverage reporting and visualization, however if you need just coverage visualization you may want to use SourceBasedCodeCoverage instead.”

For example, code coverage in Fuzzilli (googleprojectzero/fuzzilli: A JavaScript Engine Fuzzer (github.com)), Google’s state-of-the-art JavaScript engine fuzzer, utilizes simple instrumentation to respond to Fuzzilli’s process, as demonstrated in the code snippet below.

extern "C" void __sanitizer_cov_trace_pc_guard(uint32_t *guard) {
    uint32_t index = *guard;
    __shmem->edges[index / 8] |= 1 << (index % 8);
    *guard = 0;
}

The function __sanitizer_cov_trace_pc_guard() will consistently execute when a new edge is found, so no condition is necessary to interpret the new edge discovery. Then, the function changes a bit in the shared bitmap __shmem->edges to 1 (bitwise OR), and then Fuzzilli analyzes the bitmap after execution.

Other tools, like LLVM-COV (llvm-cov – emit coverage information — LLVM 19.0.0git documentation), capture code coverage information statically, providing a human-readable document after execution; however, fuzzers need to be efficient, and reading documents in the disk would affect the performance.

Getting More Information

We can modify Fuzzilli’s instrumentation and observe other resources that __sanitizer_cov_trace_pc_guard() can bring to the code coverage. The code snippet below demonstrates the Fuzzilli instrumentation with a few tweaks.

extern "C" void __sanitizer_cov_trace_pc_guard(uint32_t *guard) {
    uint32_t index = *guard;

    void *PC = __builtin_return_address(0);
    char PcDescr[1024];

    __sanitizer_symbolize_pc(PC, "%p %F %L", PcDescr, sizeof(PcDescr));
    printf("guard: %p %x PC %s\n", guard, *guard, PcDescr);

    __shmem->edges[index / 8] |= 1 << (index % 8);
    *guard = 0;
}

We already know that the function __sanitizer_cov_trace_pc_guard() is executed every time the instrumented program hits a new edge. In this case, we are utilizing the function __builtin_return_address() to collect the return addresses from every new edge hit in the target program. Now, the pointer PC has the return address information. We can utilize the __sanitizer_symbolize_pc() function to correlate the address to the symbols, providing more information about the source code file used during the execution.

Most fuzzers use only the edge information to guide the fuzzing process. However, as we will demonstrate in the next section, using the sanitizer interface can provide compelling information for security assessments.

Lab Exercise

In our laboratory, we will utilize another JavaScript engine. In this case, an old version of JerryScript JavaScript engine to create an environment.

• Operating System (OS): Ubuntu 22.04
• Target Program: JerryScript 
• Vulnerability: CVE-2023-36109

Setting Up the Environment

You can build JerryScript using the following instructions.

First, clone the repository:

$ git clone https://github.com/jerryscript-project/jerryscript.git

Enter into the JerryScript folder and checkout the 8ba0d1b6ee5a065a42f3b306771ad8e3c0d819bc commit.

$ git checkout 8ba0d1b6ee5a065a42f3b306771ad8e3c0d819bc

Fuzzilli utilizes the head 8ba0d1b6ee5a065a42f3b306771ad8e3c0d819bc for the instrumentation, and we can take advantage of the configuration done for our lab. Apply the patch available in the Fuzziilli’s repository (fuzzilli/Targets/Jerryscript/Patches/jerryscript.patch at main · googleprojectzero/fuzzilli (github.com))

$ cd jerry-main
$ wget https://github.com/googleprojectzero/fuzzilli/raw/main/Targets/Jerryscript/Patches/jerryscript.patch
$ patch < jerryscript.patch
patching file CMakeLists.txt
patching file main-fuzzilli.c
patching file main-fuzzilli.h
patching file main-options.c
patching file main-options.h
patching file main-unix.c

The instrumented file is jerry-main/main-fuzzilli.c, provided by the Fuzzilli’s patch.  It comes with the necessary to work with simple code coverage capabilities. Still, we want more, so we can use the same lines we demonstrated in the previous section to update the function __sanitizer_cov_trace_pc_guard() before the compilation. Also, adding the following header to jerry-main/main-fuzzilli.c file:

#include <sanitizer/common_interface_defs.h>

The file header describes the __sanitizer_symbolize_pc() function, which will be needed in our implementation. We will modify the function in the jerry-main/main-fuzzilli.c file.

void __sanitizer_cov_trace_pc_guard(uint32_t *guard) {
    uint32_t index = *guard;
    if(!index) return;
    index--;

    void *PC = __builtin_return_address(0);
    char PcDescr[1024];

    __sanitizer_symbolize_pc(PC, "%p %F %L", PcDescr, sizeof(PcDescr));
    printf("guard: %p %x PC %s\n", (void *)guard, *guard, PcDescr);
    __shmem->edges[index / 8] |= 1 << (index % 8);
    *guard = 0;
}

We now change the compilation configuration and disable the strip. The symbols are only needed to identify the possible vulnerable functions for our demonstration.

In the root folder CMakeLists.txt file

# Strip binary
if(ENABLE_STRIP AND NOT CMAKE_BUILD_TYPE STREQUAL "Debug")
  jerry_add_link_flags(-g)
endif()

It defaults with the -s option; change to -g to keep the symbols. Make sure that jerry-main/CMakeLists.txt contains the main-fuzzilli.c file, and then we are ready to compile. We can then build it using the Fuzzilli instructions.

$ python jerryscript/tools/build.py --compile-flag=-fsanitize-coverage=trace-pc-guard --profile=es2015-subset --lto=off --compile-flag=-D_POSIX_C_SOURCE=200809 --compile-flag=-Wno-strict-prototypes --stack-limit=15

If you have installed Clang, but the output line CMAKE_C_COMPILER_ID is displaying GNU or something else, you will have errors during the building.

$ python tools/build.py --compile-flag=-fsanitize-coverage=trace-pc-guard --profile=es2015-subset --lto=off --compile-flag=-D_POSIX_C_SOURCE=200809 --compile-flag=-Wno-strict-prototypes --stack-limit=15
-- CMAKE_BUILD_TYPE               MinSizeRel
-- CMAKE_C_COMPILER_ID            GNU
-- CMAKE_SYSTEM_NAME              Linux
-- CMAKE_SYSTEM_PROCESSOR         x86_64

You can simply change the CMakeLists.txt file, lines 28-42 to enforce Clang instead of GNU by modifying USING_GCC 1 to USING_CLANG 1, as shown below:

# Determining compiler
if(CMAKE_C_COMPILER_ID MATCHES "GNU")
  set(USING_CLANG 1)
endif()

if(CMAKE_C_COMPILER_ID MATCHES "Clang")
  set(USING_CLANG 1)
endif()

The instrumented binary will be the build/bin/jerry file.

Execution

Let’s start by disabling ASLR (Address Space Layout Randomization).

$ echo 0 | sudo tee /proc/sys/kernel/randomize_va_space

After testing, we can re-enable the ASLR by setting the value to 2.

$ echo 2 | sudo tee /proc/sys/kernel/randomize_va_space

We want to track the address to the source code file, and disabling the ASLR will help us stay aware during the analysis and not affect our results. The ASLR will not impact our lab, but keeping the addresses fixed during the fuzzing process will be fundamental.

Now, we can execute JerryScript using the PoC file for the vulnerability CVE-2023-36109 (Limesss/CVE-2023-36109: a poc for cve-2023-36109 (github.com)), as an argument to trigger the vulnerability. As described in the vulnerability description, the vulnerable function is at ecma_stringbuilder_append_raw in jerry-core/ecma/base/ecma-helpers-string.c, highlighted in the command snippet below. 

$ ./build/bin/jerry ./poc.js
[...]
guard: 0x55e17d12ac88 7bb PC 0x55e17d07ac6b in ecma_string_get_ascii_size ecma-helpers-string.c
guard: 0x55e17d12ac84 7ba PC 0x55e17d07acfe in ecma_string_get_ascii_size ecma-helpers-string.c
guard: 0x55e17d12ac94 7be PC 0x55e17d07ad46 in ecma_string_get_size (/jerryscript/build/bin/jerry+0x44d46) (BuildId: 9588e1efabff4190fd492d05d3710c7810323407)
guard: 0x55e17d12e87c 16b8 PC 0x55e17d09dfe1 in ecma_regexp_replace_helper (/jerryscript/build/bin/jerry+0x67fe1) (BuildId: 9588e1efabff4190fd492d05d3710c7810323407)
guard: 0x55e17d12ae04 81a PC 0x55e17d07bb64 in ecma_stringbuilder_append_raw (/jerryscript/build/bin/jerry+0x45b64) (BuildId: 9588e1efabff4190fd492d05d3710c7810323407)
guard: 0x55e17d12e890 16bd PC 0x55e17d09e053 in ecma_regexp_replace_helper (/jerryscript/build/bin/jerry+0x68053) (BuildId: 9588e1efabff4190fd492d05d3710c7810323407)
guard: 0x55e17d12e8b8 16c7 PC 0x55e17d09e0f1 in ecma_regexp_replace_helper (/jerryscript/build/bin/jerry+0x680f1) (BuildId: 9588e1efabff4190fd492d05d3710c7810323407)
guard: 0x55e17d133508 29db PC 0x55e17d0cc292 in ecma_builtin_replace_substitute (/jerryscript/build/bin/jerry+0x96292) (BuildId: 9588e1efabff4190fd492d05d3710c7810323407)
guard: 0x55e17d133528 29e3 PC 0x55e17d0cc5bd in ecma_builtin_replace_substitute (/jerryscript/build/bin/jerry+0x965bd) (BuildId: 9588e1efabff4190fd492d05d3710c7810323407)
guard: 0x55e17d12f078 18b7 PC 0x55e17d040a78 in jmem_heap_realloc_block (/jerryscript/build/bin/jerry+0xaa78) (BuildId: 9588e1efabff4190fd492d05d3710c7810323407)
guard: 0x55e17d12f088 18bb PC 0x55e17d040ab4 in jmem_heap_realloc_block (/jerryscript/build/bin/jerry+0xaab4) (BuildId: 9588e1efabff4190fd492d05d3710c7810323407)
guard: 0x55e17d12f08c 18bc PC 0x55e17d040c26 in jmem_heap_realloc_block (/jerryscript/build/bin/jerry+0xac26) (BuildId: 9588e1efabff4190fd492d05d3710c7810323407)
guard: 0x55e17d12f094 18be PC 0x55e17d040ca3 in jmem_heap_realloc_block (/jerryscript/build/bin/jerry+0xaca3) (BuildId: 9588e1efabff4190fd492d05d3710c7810323407)
UndefinedBehaviorSanitizer:DEADLYSIGNAL
==27636==ERROR: UndefinedBehaviorSanitizer: SEGV on unknown address 0x55e27da7950c (pc 0x7fe341fa092b bp 0x000000000000 sp 0x7ffc77634f18 T27636)
==27636==The signal is caused by a READ memory access.
    #0 0x7fe341fa092b  string/../sysdeps/x86_64/multiarch/memmove-vec-unaligned-erms.S:513
    #1 0x55e17d0cc3bb in ecma_builtin_replace_substitute (/jerryscript/build/bin/jerry+0x963bb) (BuildId: 9588e1efabff4190fd492d05d3710c7810323407)
    #2 0x55e17d09e103 in ecma_regexp_replace_helper (/jerryscript/build/bin/jerry+0x68103) (BuildId: 9588e1efabff4190fd492d05d3710c7810323407)
    #3 0x55e17d084a23 in ecma_builtin_dispatch_call (/jerryscript/build/bin/jerry+0x4ea23) (BuildId: 9588e1efabff4190fd492d05d3710c7810323407)
    #4 0x55e17d090ddc in ecma_op_function_call_native ecma-function-object.c
    #5 0x55e17d0909c1 in ecma_op_function_call (/jerryscript/build/bin/jerry+0x5a9c1) (BuildId: 9588e1efabff4190fd492d05d3710c7810323407)
    #6 0x55e17d0d4743 in ecma_builtin_string_prototype_object_replace_helper ecma-builtin-string-prototype.c
    #7 0x55e17d084a23 in ecma_builtin_dispatch_call (/jerryscript/build/bin/jerry+0x4ea23) (BuildId: 9588e1efabff4190fd492d05d3710c7810323407)
    #8 0x55e17d090ddc in ecma_op_function_call_native ecma-function-object.c
    #9 0x55e17d0909c1 in ecma_op_function_call (/jerryscript/build/bin/jerry+0x5a9c1) (BuildId: 9588e1efabff4190fd492d05d3710c7810323407)
    #10 0x55e17d0b929f in vm_execute (/jerryscript/build/bin/jerry+0x8329f) (BuildId: 9588e1efabff4190fd492d05d3710c7810323407)
    #11 0x55e17d0b8d4a in vm_run (/jerryscript/build/bin/jerry+0x82d4a) (BuildId: 9588e1efabff4190fd492d05d3710c7810323407)
    #12 0x55e17d0b8dd0 in vm_run_global (/jerryscript/build/bin/jerry+0x82dd0) (BuildId: 9588e1efabff4190fd492d05d3710c7810323407)
    #13 0x55e17d06d4a5 in jerry_run (/jerryscript/build/bin/jerry+0x374a5) (BuildId: 9588e1efabff4190fd492d05d3710c7810323407)
    #14 0x55e17d069e32 in main (/jerryscript/build/bin/jerry+0x33e32) (BuildId: 9588e1efabff4190fd492d05d3710c7810323407)
    #15 0x7fe341e29d8f in __libc_start_call_main csu/../sysdeps/nptl/libc_start_call_main.h:58:16
    #16 0x7fe341e29e3f in __libc_start_main csu/../csu/libc-start.c:392:3
    #17 0x55e17d0412d4 in _start (/jerryscript/build/bin/jerry+0xb2d4) (BuildId: 9588e1efabff4190fd492d05d3710c7810323407)
UndefinedBehaviorSanitizer can not provide additional info.
SUMMARY: UndefinedBehaviorSanitizer: SEGV string/../sysdeps/x86_64/multiarch/memmove-vec-unaligned-erms.S:513 
==27636==ABORTING

Using this technique, we could identify the root cause of the vulnerability in the function ecma_stringbuilder_append_raw() address in the stack trace. 

However, if we rely only on the sanitizer to check the stack trace, we won’t be able to see the vulnerable function name in our output:

$ ./build/bin/jerry ./poc.js 
[COV] no shared memory bitmap available, skipping
[COV] edge counters initialized. Shared memory: (null) with 14587 edges
UndefinedBehaviorSanitizer:DEADLYSIGNAL
==54331==ERROR: UndefinedBehaviorSanitizer: SEGV on unknown address 0x5622ae01350c (pc 0x7fc1925a092b bp 0x000000000000 sp 0x7ffed516b838 T54331)
==54331==The signal is caused by a READ memory access.
    #0 0x7fc1925a092b  string/../sysdeps/x86_64/multiarch/memmove-vec-unaligned-erms.S:513
    #1 0x5621ad66636b in ecma_builtin_replace_substitute (/jerryscript/build/bin/jerry+0x9636b) (BuildId: 15a3c1cd9721e9f1b4e15fade2028ddca6dc542a)
    #2 0x5621ad6380b3 in ecma_regexp_replace_helper (/jerryscript/build/bin/jerry+0x680b3) (BuildId: 15a3c1cd9721e9f1b4e15fade2028ddca6dc542a)
    #3 0x5621ad61e9d3 in ecma_builtin_dispatch_call (/jerryscript/build/bin/jerry+0x4e9d3) (BuildId: 15a3c1cd9721e9f1b4e15fade2028ddca6dc542a)
    #4 0x5621ad62ad8c in ecma_op_function_call_native ecma-function-object.c
    #5 0x5621ad62a971 in ecma_op_function_call (/jerryscript/build/bin/jerry+0x5a971) (BuildId: 15a3c1cd9721e9f1b4e15fade2028ddca6dc542a)
    #6 0x5621ad66e6f3 in ecma_builtin_string_prototype_object_replace_helper ecma-builtin-string-prototype.c
    #7 0x5621ad61e9d3 in ecma_builtin_dispatch_call (/jerryscript/build/bin/jerry+0x4e9d3) (BuildId: 15a3c1cd9721e9f1b4e15fade2028ddca6dc542a)
    #8 0x5621ad62ad8c in ecma_op_function_call_native ecma-function-object.c
    #9 0x5621ad62a971 in ecma_op_function_call (/jerryscript/build/bin/jerry+0x5a971) (BuildId: 15a3c1cd9721e9f1b4e15fade2028ddca6dc542a)
    #10 0x5621ad65324f in vm_execute (/jerryscript/build/bin/jerry+0x8324f) (BuildId: 15a3c1cd9721e9f1b4e15fade2028ddca6dc542a)
    #11 0x5621ad652cfa in vm_run (/jerryscript/build/bin/jerry+0x82cfa) (BuildId: 15a3c1cd9721e9f1b4e15fade2028ddca6dc542a)
    #12 0x5621ad652d80 in vm_run_global (/jerryscript/build/bin/jerry+0x82d80) (BuildId: 15a3c1cd9721e9f1b4e15fade2028ddca6dc542a)
    #13 0x5621ad607455 in jerry_run (/jerryscript/build/bin/jerry+0x37455) (BuildId: 15a3c1cd9721e9f1b4e15fade2028ddca6dc542a)
    #14 0x5621ad603e32 in main (/jerryscript/build/bin/jerry+0x33e32) (BuildId: 15a3c1cd9721e9f1b4e15fade2028ddca6dc542a)
    #15 0x7fc192429d8f in __libc_start_call_main csu/../sysdeps/nptl/libc_start_call_main.h:58:16
    #16 0x7fc192429e3f in __libc_start_main csu/../csu/libc-start.c:392:3
    #17 0x5621ad5db2d4 in _start (/jerryscript/build/bin/jerry+0xb2d4) (BuildId: 15a3c1cd9721e9f1b4e15fade2028ddca6dc542a)

UndefinedBehaviorSanitizer can not provide additional info.
SUMMARY: UndefinedBehaviorSanitizer: SEGV string/../sysdeps/x86_64/multiarch/memmove-vec-unaligned-erms.S:513 
==54331==ABORTING

This behavior happens because the vulnerability occurs far from the last execution in the program. Usually, the primary action would be debugging to identify the address of the vulnerable function in memory. 

Additional Considerations

The vulnerable address or address space could be used as a guide during fuzzing. We can then compare the PC to the specific address space and instruct the fuzzer to focus on a path by mutating the same input in an attempt to cause other vulnerabilities in the same function or file.
For example, we can also feed data related to historical vulnerability identification, correlate dangerous files to their address space in a specific project and include them into the instrumentation, and give feedback to the fuzzer to achieve a more focused fuzzing campaign.

We do not necessarily need to use __sanitizer_symbolize_pc for the fuzzing process; this is done only to demonstrate the function and file utilized by each address. Our methodology would only require void *PC = __builtin_return_address(0). The PC will point to the current PC address in the execution, which is the only information needed for the comparison and guiding process.

As we demonstrated above, we can retrieve more information about the stack trace and identify vulnerable execution paths. So, let’s look at Fuzzilli’s basic algorithm, described in their NDSS paper.

In line 12, it is defined that if a new edge is found, the JavaScript code is converted back to its Intermediate Language (IL) (line 13), and the input is added to the corpus for further mutations in line 14.

What can we change to improve the algorithm? Since we have more information about historical vulnerability identification and stack traces, I think that’s a good exercise for the readers.

Conclusion

We demonstrated that we can track the real-time stack trace of a target program by extending Fuzzilli’s instrumentation. By having better visibility into the return address information and its associated source code files, it’s easier to supply the fuzzer with additional paths that can produce interesting results.

Ultimately, this instrumentation technique can be applied to any fuzzer that can take advantage of code coverage capabilities. We intend to use this modified instrumentation output technique in a part 2 blog post at a later date, showing how it can be used to direct the fuzzer to potentially interesting execution paths.

The post Coverage Guided Fuzzing – Extending Instrumentation to Hunt Down Bugs Faster! appeared first on Include Security Research Blog.

I wrote last week about the problems arising from the massive backlog of vulnerabilities at the U.S. National Vulnerability Database.  

Thousands of CVEs are still without analysis data, and the once-reliable database of every single vulnerability that’s disclosed and/or patched is now so far behind, it could take up to 100 days for the National Institute of Standards and Technology (NIST) to catch up, and that would be assuming no new vulnerabilities are disclosed during that period. 

While the U.S. government and NIST try to sort out a potential solution, and hopefully await more funding and restructuring, NIST says it’s hoping to launch a consortium to help either rebuild the NVD or create a replacement.  

Other security experts have floated the idea of other companies or organizations creating a brand-new solution of their own. The main problem with that is, what’s in it for them?  

What works about the NVD is that it’s funded by the U.S. government, so the money is always coming in to help fund the workforce and at least gives MITRE and the other private companies who contribute to the NVD motivation to keep working on it. 

To start up a whole new database of *every* CVE out there would take countless man-hours, and then what at the end? Would the company or person(s) who created it start charging for access? 

Several open-source solutions haveman-hours popped up over the past few weeks, such as “NVD Data Overrides,” which “is meant to provide additional data that is currently missing from NVD.” However, these types of volunteer projects still can’t assign CVSS scores, because only the NVD is authorized to hand out official NVD CVSS scores. 

This brings up another problem for private companies that may want to develop a solution: Do they want to play referee?  

Sometimes, when there’s a disagreement on how severe a vulnerability is and what severity score to assign it, the NVD will weigh in and provide their own, independently calculated CVSS score. Who really wants to be the “bad guy” to get between a massive tech company like Microsoft or Apple and a security researcher saying a vulnerability is a 9.5 out of 10 CVSS? 

I absolutely give major credit to any volunteers or open-source developers who are working on their own solutions for essentially nothing — but how long can we expect them to keep maintaining these databases? 

Unfortunately, I don’t have a great answer for this, either. I’m far from an expert on vulnerability management, nor do I have any connections to the federal government. But I do feel the onus is on the government to come up with a solution, and potentially provide incentives for companies and researchers to participate in this new proposed consortium because I don’t see the incentives there for the private sector to come up with their own solution.  

The one big thing 

ArcaneDoor is a new campaign that is the latest example of state-sponsored actors targeting perimeter network devices from multiple vendors. Talos and Cisco PSIRT recently identified a previously unknown actor, now tracked as UAT4356 by Talos and STORM-1849 by the Microsoft Threat Intelligence Center. This actor utilized bespoke tooling that demonstrated a clear focus on espionage and an in-depth knowledge of the devices that they targeted, hallmarks of a sophisticated state-sponsored actor. UAT4356 deployed two backdoors as components of this campaign, “Line Runner” and “Line Dancer,” which were used collectively to conduct malicious actions on-target, which included configuration modification, reconnaissance, network traffic capture/exfiltration and potentially lateral movement.   

Why do I care? 

Gaining a foothold on these devices allows an actor to directly pivot into an organization, reroute or modify traffic and monitor network communications. In the past two years, we have seen a dramatic and sustained increase in the targeting of these devices in areas such as telecommunications providers and energy sector organizations — critical infrastructure entities that are likely strategic targets of interest for many foreign governments. As a critical path for data into and out of the network, these devices need to be routinely and promptly patched; using up-to-date hardware and software versions and configurations; and be closely monitored from a security perspective. 

So now what? 

There are some known indicators of compromise that customers can look for if they suspect they may have been targeted in this campaign. First, organizations should look for any flows to/from ASA devices to any of the IP addresses present in the IOC list provided at the bottom of this blog. This is one indication that further investigation is necessary. Potential targets can also follow the steps detailed in the Cisco ASA Forensic Investigation Procedures for First Responders. When following these procedures, first responders should NOT attempt to collect a core dump or reboot the device if they believe that the device has been compromised, based on the lina memory region output. Talos also released some Snort signatures to detect the activity on the wire including access attempts. Snort Signatures 63139, 62949 and 45575 have been released to detect the implants or associated behaviors. 

Top security headlines of the week 

A previously known Windows print spooler bug is still being actively exploited, according to Microsoft. The company’s threat research team recently disclosed that APT28, a well-known Russian state-sponsored actor, is exploiting the vulnerability to deliver a previously unknown malware called “GooseEgg.” Microsoft disclosed and patched CVE-2022-38028 in October 2022, but APT28 may have been exploiting it as far back as 2020. The actor’s exploitation involved modifying a JavaScript constraints file in the printer spooler and executing it with SYSTEM-level permissions. The new research prompted the U.S. Cybersecurity and Infrastructure Security Agency (CISA) to add CVE-2022-38028 to its Known Exploited Vulnerabilities (KEV) catalog. If installed, GooseEgg can load other applications with System-level permissions and allow the adversary to execute remote code on the targeted device or deploy other backdoors. Another set of print spooler vulnerabilities, called PrintNightmare, made headlines in July 2021, though no one reported active exploitation of that vulnerability at the time. (SC Magazine, Security Week) 

A new investigation revealed how members of the group Scattered Spider are partnering with Russian state-sponsored actors to carry out ransomware attacks. Scattered Spider is made up of younger individuals based out of the U.S., U.K. and Canada. They are primarily English speakers who have been blamed for several notable ransomware attacks, including one against MGM Casinos that disrupted operations at several casinos and hotels last year. The group specializes in social engineering, more recently using LinkedIn to steal employee information and use that to infiltrate corporate networks. Members, some as young as teenagers, are connecting over the dark web and online forums like Discord and use their advanced knowledge of Western civilization to provide crucial details to Russian actors. The “60 Minutes” investigation also included new details about The Community (aka “The Comm,” the online collection of hackers who like to brag about their recent cybercrimes, often through Telegram. (CBS News) 

The U.S. government has re-upped a law that expands government surveillance by opening the door for private companies to partner with the government on these types of activities. The controversial Foreign Intelligence Surveillance Act (FISA) was re-approved just hours after it lapsed. The White House and proponents in U.S. Congress argued that the powers granted in Section 702 of the FISA helps prevent the spread of terrorism and cyber attacks and that any lapse in those powers would harm the government’s ability to gather crucial intelligence. However, privacy advocates say that the FISA is an overreach, and provides too much power for private companies to potentially spy on consumers. The bill also includes a new definition of “electronic communications service provider,” which could allow the U.S. government to force Big Tech companies and telecommunications providers to hand over users’ data if requested. (NBC News, TechCrunch) 

Can’t get enough Talos? 

• Talos Takes Ep. #180: What are the dangers of enabling sideloading and third-party apps? 
• Suspected CoralRaider continues to expand victimology using three information stealers 
• Brute-force attacks surge worldwide, warns Cisco Talos    
• Cisco Warns of Massive Surge in Password-Spraying Attacks on VPNs 
• Rare Computer Virus Detected in Ukrainian Network, Confidential Document Potentially Compromised 

Upcoming events where you can find Talos 

CARO Workshop 2024 (May 1 - 3) 

Arlington, Virginia

Over the past year, we’ve observed a substantial uptick in attacks by YoroTrooper, a relatively nascent espionage-oriented threat actor operating against the Commonwealth of Independent Countries (CIS) since at least 2022. Asheer Malhotra's presentation at CARO 2024 will provide an overview of their various campaigns detailing the commodity and custom-built malware employed by the actor, their discovery and evolution in tactics. He will present a timeline of successful intrusions carried out by YoroTrooper targeting high-value individuals associated with CIS government agencies over the last two years.

RSA (May 6 - 9) 

San Francisco, California    

Cisco Live (June 2 - 6) 

Las Vegas, Nevada  

Most prevalent malware files from Talos telemetry over the past week 

This section will be on a brief hiatus while we work through some technical difficulties. Several open-source solutions have

Infosec and Cyber Work Hacks podcast want to help you pass the CCNA exam! So, for today’s hack, let’s talk boot camps. The CCNA is an intimidating exam, especially if you’re trying to go it alone, just you and your self-study book. That’s why I’d like to introduce you to Infosec’s CCNA boot camp instructor, Wilfredo Lanz! He will explain what the Infosec 5-day CCNA boot camp is like, the learning and memorizing strategies you’ll employ and how boot camp training can help you pass on the first try. Lanz helps his students with every networking question, and students who commit to those five intensive days will see significant results. 

0:00 - What is a CCNA boot camp like? 
1:40 - Boot camp training versus university
6:37 - Do I need to bring anything to CCNA boot camp?
7:23 - Take CCNA exam after boot camp
8:25 - Advice for taking a CCNA boot camp
9:46 - Outro

About Infosec
Infosec’s mission is to put people at the center of cybersecurity. We help IT and security professionals advance their careers with skills development and certifications while empowering all employees with security awareness and phishing training to stay cyber-safe at work and home. More than 70% of the Fortune 500 have relied on Infosec Skills to develop their security talent, and more than 5 million learners worldwide are more cyber-resilient from Infosec IQ’s security awareness training. Learn more at infosecinstitute.com.

December 2023 Windows Updates brought a patch for CVE-2023-35628, a memory corruption vulnerability that could potentially lead to remote code execution when an application on user's computer tried to access a URL provided by an attacker.

Security researcher  Ben Barnea of Akamai, who found this vulnerability and reported it to Microsoft, wrote a detailed article and published a simple and effective POC. These allowed us to reproduce the issue and create a micropatch for affected legacy Windows systems, which are no longer receiving security updates from Microsoft. 

The Vulnerability

The vulnerability resides inside the CrackUrlFile function in iertutil.dll. In July 2023, Microsoft added some code to this function that introduced the vulnerability, whereby a heap free operation is made on an invalid pointer when the provided URL is properly formatted as described in Ben's article.

CrackUrlFile is a fairly generic function and can be used by various processes and applications. Ben demonstrated the vulnerability with a simple .lnk file, which immediately crashes Windows Explorer when the directory with such file is displayed to the user. His article also mentions a possibility of triggering the vulnerability through an email message shown in Outlook, and Microsoft's advisory adds an Instant Messenger message as a possible attack vector.

Our Micropatch

We patched this issue in the same way Microsoft did, by replacing the flawed code that changed the pointer to the URL with corrected code that doesn't.

Let's see our patch in action. The video below first shows an empty Windows Event Log and a malicious .lnk file in the Downloads folder pointing to file://./UNC/C:/Akamai.com/file.wav. (Note that displaying this .lnk file does not crash Windows Explorer because 0patch is enabled and the vulnerability already patched by it.)

Then, 0patch is disabled, which un-applies all 0patch micropatches from running processes, including the micropatch for CVE-2023-35628 from explorer.exe process. Opening the Downloads folder leads to immediate crashing of explorer.exe without any other user interaction as the process tries to determine an icon for the .lnk file, leading to the "malicious" URL being processed by vulnerable CrackUrlFile function.

Finally, 0patch is re-enabled, and the malicious .lnk file is unable to crash Windows Explorer because the vulnerability was removed from the process.

Micropatch Availability

Micropatches were written for the following security-adopted versions of Windows with all available Windows Updates installed:

1. Windows 11 v21H2 - fully updated
2. Windows Server 2012 R2 - fully updated with no ESU
   

Vulnerabilities like these get discovered on a regular basis, and attackers know about them all. If you're using Windows that aren't receiving official security updates anymore, 0patch will make sure these vulnerabilities won't be exploited on your computers - and you won't even have to know or care about these things.

If you're new to 0patch, create a free account in 0patch Central, then install and register 0patch Agent from 0patch.com, and email [email protected] for a trial. Everything else will happen automatically. No computer reboot will be needed.

We would like to thank  Ben Barnea of Akamai for sharing their analysis and POC, which made it possible for us to create a micropatch for this issue.

Business email compromise (BEC) was the top threat observed by Cisco Talos Incident Response (Talos IR) in the first quarter of 2024, accounting for nearly half of engagements, which is more than double what was observed in the previous quarter.  

The most observed means of gaining initial access was the use of compromised credentials on valid accounts, which accounted for 29 percent of engagements. The high number of BEC attacks likely played a significant role in valid accounts being the top attack vector this quarter. Weaknesses involving multi-factor authentication (MFA) were observed within nearly half of engagements this quarter, with the top observed weakness being users accepting unauthorized push notifications, occurring within 25 percent of engagements.  

There was a slight decrease in ransomware this quarter, accounting for 17 percent of engagements. Talos IR responded to new variants of Phobos and Akira ransomware for the first time this quarter. 

Manufacturing was the most targeted vertical this quarter, closely followed by education, a continuation from Q4 2024 where manufacturing and education were also two of the most targeted verticals. There was a 20 percent increase in manufacturing engagements from the previous quarter. 

The manufacturing sector faces unique challenges due to its inherently low tolerance for operational downtime. This quarter, Talos IR observed a wide range of threat activity targeting manufacturing organizations including financially motivated attacks, such as BEC and ransomware, and some brute force activity targeting virtual private network (VPN) infrastructure. The use of compromised credentials on valid accounts was the top observed attack vector within attacks targeting the manufacturing sector this quarter, which represents a change from the previous quarter when the top attack vector observed in these types of engagements was exploiting vulnerabilities in public-facing applications.   

Watch discussion on the report's biggest trends

Surge in BEC 

Within BEC attacks, adversaries will send phishing emails appearing to be from a known or reputable source making a valid request, such as updating payroll direct deposit information. BEC attacks can have many motivations, often financially driven, aimed at tricking organizations into transferring funds or sensitive information to malicious actors.  

BEC offers adversaries the advantage of impersonating trusted contacts to facilitate internal spearphishing attacks that can bypass traditional external defenses and increase the likelihood of deception, widespread malware infections and data theft. 

In one engagement, adversaries performed a password-spraying attack and MFA exhaustion attacks against several employee accounts. There was a lack of proper MFA implementation across all the impacted accounts, leading to the adversaries gaining access to at least two accounts using single-factor authentication. The organization detected and disrupted the attack before adversaries could further their access or perform additional post-compromise activities.    

In another cluster of activity, several employees received spear-phishing emails that contained links that, when clicked, led to a redirection chain of web pages ultimately landing on a legitimate single sign-on (SSO) prompt that was pre-populated with each victim’s email address. The attack was unsuccessful because none of the employees interacted with the email, which was likely due to multiple red flags. For example, the email was unexpected and sent from an external email address, and there was small text within the email that referred to the email as a fax, which was all indicators of a phishing attempt. 

Ransomware trends 

Ransomware accounted for 17 percent of engagements this quarter, an 11 percent decrease from the previous quarter. Talos IR observed new variants of Akira and Phobos ransomware for the first time this quarter. 

Akira 

Talos IR responded to an Akira ransomware attack for the first time this quarter in an engagement where affiliates deployed the latest ESXi version, “Akira_v2,” as well as a Windows-based variant of Akira named “Megazord.” These new Akira variants are written in the Rust programming language, which is a notable change from the previously used C++ and Crypto++ programming languages.  

Talos IR could not determine how initial access was gained, which is common because ransomware attacks often involve multi-stage attack strategies that add additional complexity during the investigation process. Once inside the network, the adversaries began collecting credentials from the memory of the Local Security Authority Subsystem Service (LSASS) and the New Technology Directory Services Directory Information Tree (NTDS.dit) database, where Active Directory data is stored, and leveraged Remote Desktop Protocol (RDP) for lateral movement. Prior to encryption, Megazord ransomware began executing several commands to disable tools and impair defenses, including “net stop” and “taskkill.” Akira_v2 appended the file extension “.akiranew” during encryption, while Megazord ransomware appended the file extension “.powerranges”.   

First discovered in early 2023, Akira operates as a ransomware-as-a-service (RaaS) model and employs a double extortion scheme that involves exfiltrating data before encryption. Akira affiliates are known to heavily target small- to medium-sized businesses within several verticals primarily located within the U.S. but have targeted organizations within the U.K., Canada, Iceland, Australia and South Korea. Akira affiliates are notorious for leveraging compromised credentials and exploiting vulnerabilities as a means of gaining initial access, such as the SQL injection vulnerability, tracked as CVE-2021-27876, affecting certain versions of Zoho ManageEngine ADSelfService Plus, and the vulnerability, tracked as CVE-2023-27532, affecting certain versions of Veeam’s Backup & Replication (VBS) software.    

Phobos 

Talos IR has previously observed variants of Phobos ransomware, such as “Faust,” but this quarter, Talos IR responded to an engagement with the “BackMyData” variant of Phobos ransomware. The adversaries leveraged Mimikatz to dump credentials from Active Directory. The adversary also installed several tools in the NirSoft product suite designed to recover passwords, such as PasswordFox and ChromePass, for additional credential enumeration. 

The adversaries used PsExec to access the domain controller before setting a registry key to permit remote desktop connections. Shortly after, the adversaries also modified the firewall to allow remote desktop connections using the Windows scripting utility, netsh. The remote access tool AnyDesk was downloaded to enable remote access as a means of persistence in the environment. Talos IR assessed with high confidence that Windows Secure Copy (WinSCP) and Secure Shell (SSH) were likely used to exfiltrate staged data. Adversaries also relied on PsExec to execute commands, such as deleting volume shadow copies, as a precursor to deploying the ransomware executable. After encryption, the ransomware appended the file extension “.fastbackdata”.   

A notable finding was the persistent use of the “Users/[username]/Music” directory as a staging area for data exfiltration to host malicious scripts, tools and malware, a common technique used by numerous ransomware affiliates to evade detection and remain persistent in the environment. Talos IR also identified a digitally signed executable, “HRSword,” developed by Beijing Huorong Network Technology. It is a tool the affiliate used during the attack for potential secure file deletion and as a defensive measure to disable endpoint protection tools, which Phobos affiliates were previously using, according to public reporting.   

Phobos ransomware first emerged in late 2018 and shared many similarities with the Crysis and Dharma ransomware families. Unlike other ransomware families, there are many variants of Phobos ransomware, such as Eking, Eight, Elbie, Devos and Faust. There is little information known about the business model leveraged by the Phobos ransomware operation. In November 2023, Cisco Talos analyzed over a thousand samples of Phobos ransomware to learn more about the affiliate structure and activity, which revealed that Phobos may operate a RaaS model due to the hundreds of contact emails and IDs associated with Phobos campaigns, indicating the malware has a dispersed affiliate base. Talos assessed with moderate confidence that the Phobos ransomware operation is actively managed by a central authority, as there is only one private key capable of decryption in all observed campaigns. 

Other observed threats  

Talos IR responded to an attack where adversaries were attempting to brute force several Cisco Adaptive Security Appliances (ASAs). Although the adversaries were unsuccessful in their attack, this activity is in line with the recently observed trend affecting VPN services. 

Cisco Talos has recently seen an increase in malicious activity targeting VPN services, web application authentication interfaces, and Secure Shell (SSH) globally. Since at least March 18, Cisco has observed scanning and brute force activity sourcing from The Onion Router (TOR) exit nodes and other anonymous tunnels and proxies. 

Depending on the target environment, a successful attack could result in unauthorized access to a target network, possibly leading to account lockouts and denial-of-service (DoS) conditions. The brute force attempts include a combination of generic usernames and valid usernames unique to specific organizations. The activity seems indiscriminate and has been observed across multiple industry verticals and geographic regions. 

Initial vectors 

The most observed means of gaining initial access was the use of compromised credentials on valid accounts, accounting for 29 percent of engagements, a continuation of a trend from the previous quarter when valid accounts were also a top attack vector. 

Security weaknesses 

For the first time, users accepting unauthorized MFA push notifications was the top observed security weakness, accounting for 25 percent of engagements this quarter. The lack of proper MFA implementation closely followed, accounting for 21 percent of engagements, a 44 percent decrease from the previous quarter. 

Users must have a clear understanding of the appropriate business response protocols when their devices are overwhelmed with an excessive volume of push notifications. Talos IR recommends organizations educate their employees about the specific channels and points of contact for reporting these incidents. Prompt and accurate reporting enables security teams to quickly identify the nature of the issue and implement the necessary measures to address the situation effectively. Organizations should also consider implementing number-matching in MFA applications to provide an additional layer of security to prevent users from accepting malicious MFA push notifications. 

Talos IR recommends implementing MFA on all critical services including all remote access and identity access management (IAM) services. MFA will be the most effective method for the prevention of remote-based compromises. It also prevents lateral movement by requiring all administrative users to provide a second form of authentication. Organizations can set up alerting for single-factor authentication to quickly identify potential gaps. 

Top observed MITRE ATT&CK techniques 

The table below represents the MITRE ATT&CK techniques observed in this quarter’s IR engagements and includes relevant examples and the number of times seen. Given that some techniques can fall under multiple tactics, we grouped them under the most relevant tactic based on the way they were leveraged. Please note, this is not an exhaustive list. 

Key findings from the MITRE ATT&CK framework include:  

• Remote access software, such as SplashTop and AnyDesk, were used in 17 percent of engagements this quarter, a 20 percent decrease from the previous quarter.  
• The use of email hiding rules was the top observed defense evasion technique, accounting for 21 percent of engagements this quarter.   
• Scheduled tasks were leveraged by adversaries the most this quarter for persistence, accounting for 17 percent of engagements this quarter, a 33 percent increase from the previous quarter.  
• The abuse of remote services, such as RDP, SSH, SMB and WinRM, more than doubled this quarter compared to the previous quarter, accounting for nearly 60 percent of engagements. 

Espionage is a network packet sniffer that intercepts large amounts of data being passed through an interface. The tool allows users to to run normal and verbose traffic analysis that shows a live feed of traffic, revealing packet direction, protocols, flags, etc. Espionage can also spoof ARP so, all data sent by the target gets redirected through the attacker (MiTM). Espionage supports IPv4, TCP/UDP, ICMP, and HTTP. Espionag e was written in Python 3.8 but it also supports version 3.6. This is the first version of the tool so please contact the developer if you want to help contribute and add more to Espionage. Note: This is not a Scapy wrapper, scapylib only assists with HTTP requests and ARP.

Installation

1: git clone https://www.github.com/josh0xA/Espionage.git
2: cd Espionage
3: sudo python3 -m pip install -r requirments.txt
4: sudo python3 espionage.py --help

Usage

1. sudo python3 espionage.py --normal --iface wlan0 -f capture_output.pcap
   Command 1 will execute a clean packet sniff and save the output to the pcap file provided. Replace wlan0 with whatever your network interface is.
   
2. sudo python3 espionage.py --verbose --iface wlan0 -f capture_output.pcap
   Command 2 will execute a more detailed (verbose) packet sniff and save the output to the pcap file provided.
   
3. sudo python3 espionage.py --normal --iface wlan0
   Command 3 will still execute a clean packet sniff however, it will not save the data to a pcap file. Saving the sniff is recommended.
   
4. sudo python3 espionage.py --verbose --httpraw --iface wlan0
   Command 4 will execute a verbose packet sniff and will also show raw http/tcp packet data in bytes.
   
5. sudo python3 espionage.py --target <target-ip-address> --iface wlan0
   Command 5 will ARP spoof the target ip address and all data being sent will be routed back to the attackers machine (you/localhost).
   
6. sudo python3 espionage.py --iface wlan0 --onlyhttp
   Command 6 will only display sniffed packets on port 80 utilizing the HTTP protocol.
   
7. sudo python3 espionage.py --iface wlan0 --onlyhttpsecure
   Command 7 will only display sniffed packets on port 443 utilizing the HTTPS (secured) protocol.
   
8. sudo python3 espionage.py --iface wlan0 --urlonly
   Command 8 will only sniff and return sniffed urls visited by the victum. (works best with sslstrip).
   
   
9. Press Ctrl+C in-order to stop the packet interception and write the output to file.
   

Menu

usage: espionage.py [-h] [--version] [-n] [-v] [-url] [-o] [-ohs] [-hr] [-f FILENAME] -i IFACE
                    [-t TARGET]

optional arguments:
  -h, --help            show this help message and exit
  --version             returns the packet sniffers version.
  -n, --normal          executes a cleaner interception, less sophisticated.
  -v, --verbose         (recommended) executes a more in-depth packet interception/sniff.
  -url, --urlonly       only sniffs visited urls using http/https.
  -o, --onlyhttp        sniffs only tcp/http data, returns urls visited.
  -ohs, --onlyhttpsecure
                        sniffs only https data, (port 443).
  -hr, --httpraw        displays raw packet data (byte order) recieved or sent on port 80.

(Recommended) arguments for data output (.pcap):
  -f FILENAME, --filename FILENAME
                        name of file to store the output (make extension '.pcap').

(Required) arguments required for execution:
  -i IFACE, --iface IFACE
                        specify network interface (ie. wlan0, eth0, wlan1, etc.)

(ARP Spoofing) required arguments in-order to use the ARP Spoofing utility:
  -t TARGET, --target TARGET

Writeup

A simple medium writeup can be found here:
Click Here For The Official Medium Article

Ethical Notice

The developer of this program, Josh Schiavone, written the following code for educational and ethical purposes only. The data sniffed/intercepted is not to be used for malicous intent. Josh Schiavone is not responsible or liable for misuse of this penetration testing tool. May God bless you all.

License

MIT License
Copyright (c) 2024 Josh Schiavone

Authored by Willem Zeeman and Yun Zheng Hu

This blog is part of a series written by various Dutch cyber security firms that have collaborated on the Cactus ransomware group, which exploits Qlik Sense servers for initial access. To view all of them please check the central blog by Dutch special interest group Cyberveilig Nederland [¹]

The effectiveness of the public-private partnership called Melissa [²] is increasingly evident. The Melissa partnership, which includes Fox-IT, has identified overlap in a specific ransomware tactic. Multiple partners, sharing information from incident response engagements for their clients, found that the Cactus ransomware group uses a particular method for initial access. Following that discovery, NCC Group’s Fox-IT developed a fingerprinting technique to identify which systems around the world are vulnerable to this method of initial access or, even more critically, are already compromised.

Qlik Sense vulnerabilities

Qlik Sense, a popular data visualisation and business intelligence tool, has recently become a focal point in cybersecurity discussions. This tool, designed to aid businesses in data analysis, has been identified as a key entry point for cyberattacks by the Cactus ransomware group.

The Cactus ransomware campaign

Since November 2023, the Cactus ransomware group has been actively targeting vulnerable Qlik Sense servers. These attacks are not just about exploiting software vulnerabilities; they also involve a psychological component where Cactus misleads its victims with fabricated stories about the breach. This likely is part of their strategy to obscure their actual method of entry, thus complicating mitigation and response efforts for the affected organizations.

For those looking for in-depth coverage of these exploits, the Arctic Wolf blog [³] provides detailed insights into the specific vulnerabilities being exploited, notably CVE-2023-41266, CVE-2023-41265 also known as ZeroQlik, and potentially CVE-2023-48365 also known as DoubleQlik.

Threat statistics and collaborative action

The scope of this threat is significant. In total, we identified 5205 Qlik Sense servers, 3143 servers seem to be vulnerable to the exploits used by the Cactus group. This is based on the initial scan on 17 April 2024. Closer to home in the Netherlands, we’ve identified 241 vulnerable systems, fortunately most don’t seem to have been compromised. However, 6 Dutch systems weren’t so lucky and have already fallen victim to the Cactus group. It’s crucial to understand that “already compromised” can mean that either the ransomware has been deployed and the initial access artifacts left behind were not removed, or the system remains compromised and is potentially poised for a future ransomware attack.

Since 17 April 2024, the DIVD (Dutch Institute for Vulnerability Disclosure) and the governmental bodies NCSC (Nationaal Cyber Security Centrum) and DTC (Digital Trust Center) have teamed up to globally inform (potential) victims of cyberattacks resembling those from the Cactus ransomware group. This collaborative effort has enabled them to reach out to affected organisations worldwide, sharing crucial information to help prevent further damage where possible.

Identifying vulnerable Qlik Sense servers

Expanding on Praetorian’s thorough vulnerability research on the ZeroQlik and DoubleQlik vulnerabilities [⁴,⁵], we found a method to identify the version of a Qlik Sense server by retrieving a file called product-info.json from the server. While we acknowledge the existence of Nuclei templates for the vulnerability checks, using the server version allows for a more reliable evaluation of potential vulnerability status, e.g. whether it’s patched or end of support.

This JSON file contains the release label and version numbers by which we can identify the exact version that this Qlik Sense server is running.

Figure 1: Qlik Sense product-info.json file containing version information

Keep in mind that although Qlik Sense servers are assigned version numbers, the vendor typically refers to advisories and updates by their release label, such as “February 2022 Patch 3”.

The following cURL command can be used to retrieve the product-info.json file from a Qlik server:

curl -H "Host: localhost" -vk 'https://<ip>/resources/autogenerated/product-info.json?.ttf'

Note that we specify ?.ttf at the end of the URL to let the Qlik proxy server think that we are requesting a .ttf file, as font files can be accessed unauthenticated. Also, we set the Host header to localhost or else the server will return 400 - Bad Request - Qlik Sense, with the message The http request header is incorrect.

Retrieving this file with the ?.ttf extension trick has been fixed in the patch that addresses CVE-2023-48365 and you will always get a 302 Authenticate at this location response:

> GET /resources/autogenerated/product-info.json?.ttf HTTP/1.1
> Host: localhost
> Accept: */*
>
< HTTP/1.1 302 Authenticate at this location
< Cache-Control: no-cache, no-store, must-revalidate
< Location: https://localhost/internal_forms_authentication/?targetId=2aa7575d-3234-4980-956c-2c6929c57b71
< Content-Length: 0
<

Nevertheless, this is still a good way to determine the state of a Qlik instance, because if it redirects using 302 Authenticate at this location it is likely that the server is not vulnerable to CVE-2023-48365.

An example response from a vulnerable server would return the JSON file:

> GET /resources/autogenerated/product-info.json?.ttf HTTP/1.1
> Host: localhost
> Accept: */*
>
< HTTP/1.1 200 OK
< Set-Cookie: X-Qlik-Session=893de431-1177-46aa-88c7-b95e28c5f103; Path=/; HttpOnly; SameSite=Lax; Secure
< Cache-Control: public, max-age=3600
< Transfer-Encoding: chunked
< Content-Type: application/json;charset=utf-8
< Expires: Tue, 16 Apr 2024 08:14:56 GMT
< Last-Modified: Fri, 04 Nov 2022 23:28:24 GMT
< Accept-Ranges: bytes
< ETag: 638032013040000000
< Server: Microsoft-HTTPAPI/2.0
< Date: Tue, 16 Apr 2024 07:14:55 GMT
< Age: 136
<
{"composition":{"contentHash":"89c9087978b3f026fb100267523b5204","senseId":"qliksenseserver:14.54.21","releaseLabel":"February 2022 Patch 12","originalClassName":"Composition","deprecatedProductVersion":"4.0.X","productName":"Qlik Sense","version":"14.54.21","copyrightYearRange":"1993-2022","deploymentType":"QlikSenseServer"},
<snipped>

We utilised Censys and Google BigQuery [⁶] to compile a list of potential Qlik Sense servers accessible on the internet and conducted a version scan against them. Subsequently, we extracted the Qlik release label from the JSON response to assess vulnerability to CVE-2023-48365.

Our vulnerability assessment for DoubleQlik / CVE-2023-48365 operated on the following criteria:

1. The release label corresponds to vulnerability statuses outlined in the original ZeroQlik and DoubleQlik vendor advisories [⁷,⁸].
2. The release label is designated as End of Support (EOS) by the vendor [⁹], such as “February 2019 Patch 5”.

We consider a server non-vulnerable if:

1. The release label date is post-November 2023, as the advisory states that “November 2023” is not affected.
2. The server responded with HTTP/1.1 302 Authenticate at this location.

Any other responses were disregarded as invalid Qlik server instances.

As of 17 April 2024, and as stated in the introduction of this blog, we have detected 5205 Qlik Servers on the Internet. Among them, 3143 servers are still at risk of DoubleQlik, indicating that 60% of all Qlik Servers online remain vulnerable.

Figure 2: Qlik Sense patch status for DoubleQlik CVE-2023-48365

The majority of vulnerable Qlik servers reside in the United States (396), trailed by Italy (280), Brazil (244), the Netherlands (241), and Germany (175).

Figure 3: Top 20 countries with servers vulnerable to DoubleQlik CVE-2023-48365

Identifying compromised Qlik Sense servers

Based on insights gathered from the Arctic Wolf blog and our own incident response engagements where the Cactus ransomware was observed, it’s evident that the Cactus ransomware group continues to redirect the output of executed commands to a True Type font file named qle.ttf, likely abbreviated for “qlik exploit”.

Below are a few examples of executed commands and their output redirection by the Cactus ransomware group:

whoami /all > ../Client/qmc/fonts/qle.ttf
quser > ../Client/qmc/fonts/qle.ttf

In addition to the qle.ttf file, we have also observed instances where qle.woff was used:

Figure 4: Directory listing with exploitation artefacts left by Cactus ransomware group

It’s important to note that these font files are not part of a default Qlik Sense server installation.

We discovered that files with a font file extension such as .ttf and .woff can be accessed without any authentication, regardless of whether the server is patched. This likely explains why the Cactus ransomware group opted to store command output in font files within the fonts directory, which in turn, also serves as a useful indicator of compromise.

Our scan for both font files, found a total of 122 servers with the indicator of compromise. The United States ranked highest in exploited servers with 49 online instances carrying the indicator of compromise, followed by Spain (13), Italy (11), the United Kingdom (8), Germany (7), and then Ireland and the Netherlands (6).

Figure 5: Top 20 countries with known compromised Qlik Sense servers

Out of the 122 compromised servers, 46 were not vulnerable anymore.

When the indicator of compromise artefact is present on a remote Qlik Sense server, it can imply various scenarios. Firstly, it may suggest that remote code execution was carried out on the server, followed by subsequent patching to address the vulnerability (if the server is not vulnerable anymore). Alternatively, its presence could signify a leftover artefact from a previous security incident or unauthorised access.

While the root cause for the presence of these files is hard to determine from the outside it still is a reliable indicator of compromise.

Responsible disclosure by the DIVD
We shared our fingerprints and scan data with the Dutch Institute of Vulnerability Disclosure (DIVD), who then proceeded to issue responsible disclosure notifications to the administrators of the Qlik Sense servers.

Call to action

Ensure the security of your Qlik Sense installations by checking your current version. If your software is still supported, apply the latest patches immediately. For systems that are at the end of support, consider upgrading or replacing them to maintain robust security.

Additionally, to enhance your defences, it’s recommended to avoid exposing these services to the entire internet. Implement IP whitelisting if public access is necessary, or better yet, make them accessible only through secure remote working solutions.

If you discover you’ve been running a vulnerable version, it’s crucial to contact your (external) security experts for a thorough check-up to confirm that no breaches have occurred. Taking these steps will help safeguard your data and infrastructure from potential threats.

References

1. https://cyberveilignederland.nl/actueel/persbericht-samenwerkingsverband-melissa-vindt-diverse-nederlandse-slachtoffers-van-ransomwaregroepering-cactus ↩︎
2. https://www.ncsc.nl/actueel/nieuws/2023/oktober/3/melissa-samenwerkingsverband-ransomwarebestrijding ↩︎
3. https://arcticwolf.com/resources/blog/qlik-sense-exploited-in-cactus-ransomware-campaign/ ↩︎
4. https://www.praetorian.com/blog/qlik-sense-technical-exploit/ ↩︎
5. https://www.praetorian.com/blog/doubleqlik-bypassing-the-original-fix-for-cve-2023-41265/ ↩︎
6. https://support.censys.io/hc/en-us/articles/360038759991-Google-BigQuery-Introduction ↩︎
7. https://community.qlik.com/t5/Official-Support-Articles/Critical-Security-fixes-for-Qlik-Sense-Enterprise-for-Windows/ta-p/2110801 ↩︎
8. https://community.qlik.com/t5/Official-Support-Articles/Critical-Security-fixes-for-Qlik-Sense-Enterprise-for-Windows/ta-p/2120325 ↩︎
9. https://community.qlik.com/t5/Product-Lifecycle/Qlik-Sense-Enterprise-on-Windows-Product-Lifecycle/ta-p/1826335 ↩︎

Authored by Willem Zeeman and Yun Zheng Hu

This blog is part of a series written by various Dutch cyber security firms that have collaborated on the Cactus ransomware group, which exploits Qlik Sense servers for initial access. To view all of them please check the central blog by Dutch special interest group Cyberveilig Nederland [¹]

The effectiveness of the public-private partnership called Melissa [²] is increasingly evident. The Melissa partnership, which includes Fox-IT, has identified overlap in a specific ransomware tactic. Multiple partners, sharing information from incident response engagements for their clients, found that the Cactus ransomware group uses a particular method for initial access. Following that discovery, NCC Group’s Fox-IT developed a fingerprinting technique to identify which systems around the world are vulnerable to this method of initial access or, even more critically, are already compromised.

Qlik Sense vulnerabilities

Qlik Sense, a popular data visualisation and business intelligence tool, has recently become a focal point in cybersecurity discussions. This tool, designed to aid businesses in data analysis, has been identified as a key entry point for cyberattacks by the Cactus ransomware group.

The Cactus ransomware campaign

Since November 2023, the Cactus ransomware group has been actively targeting vulnerable Qlik Sense servers. These attacks are not just about exploiting software vulnerabilities; they also involve a psychological component where Cactus misleads its victims with fabricated stories about the breach. This likely is part of their strategy to obscure their actual method of entry, thus complicating mitigation and response efforts for the affected organizations.

For those looking for in-depth coverage of these exploits, the Arctic Wolf blog [³] provides detailed insights into the specific vulnerabilities being exploited, notably CVE-2023-41266, CVE-2023-41265 also known as ZeroQlik, and potentially CVE-2023-48365 also known as DoubleQlik.

Threat statistics and collaborative action

The scope of this threat is significant. In total, we identified 5205 Qlik Sense servers, 3143 servers seem to be vulnerable to the exploits used by the Cactus group. This is based on the initial scan on 17 April 2024. Closer to home in the Netherlands, we’ve identified 241 vulnerable systems, fortunately most don’t seem to have been compromised. However, 6 Dutch systems weren’t so lucky and have already fallen victim to the Cactus group. It’s crucial to understand that “already compromised” can mean that either the ransomware has been deployed and the initial access artifacts left behind were not removed, or the system remains compromised and is potentially poised for a future ransomware attack.

Since 17 April 2024, the DIVD (Dutch Institute for Vulnerability Disclosure) and the governmental bodies NCSC (Nationaal Cyber Security Centrum) and DTC (Digital Trust Center) have teamed up to globally inform (potential) victims of cyberattacks resembling those from the Cactus ransomware group. This collaborative effort has enabled them to reach out to affected organisations worldwide, sharing crucial information to help prevent further damage where possible.

Identifying vulnerable Qlik Sense servers

Expanding on Praetorian’s thorough vulnerability research on the ZeroQlik and DoubleQlik vulnerabilities [⁴,⁵], we found a method to identify the version of a Qlik Sense server by retrieving a file called product-info.json from the server. While we acknowledge the existence of Nuclei templates for the vulnerability checks, using the server version allows for a more reliable evaluation of potential vulnerability status, e.g. whether it’s patched or end of support.

This JSON file contains the release label and version numbers by which we can identify the exact version that this Qlik Sense server is running.

Figure 1: Qlik Sense product-info.json file containing version information

Keep in mind that although Qlik Sense servers are assigned version numbers, the vendor typically refers to advisories and updates by their release label, such as “February 2022 Patch 3”.

The following cURL command can be used to retrieve the product-info.json file from a Qlik server:

curl -H "Host: localhost" -vk 'https://<ip>/resources/autogenerated/product-info.json?.ttf'

Note that we specify ?.ttf at the end of the URL to let the Qlik proxy server think that we are requesting a .ttf file, as font files can be accessed unauthenticated. Also, we set the Host header to localhost or else the server will return 400 - Bad Request - Qlik Sense, with the message The http request header is incorrect.

Retrieving this file with the ?.ttf extension trick has been fixed in the patch that addresses CVE-2023-48365 and you will always get a 302 Authenticate at this location response:

> GET /resources/autogenerated/product-info.json?.ttf HTTP/1.1
> Host: localhost
> Accept: */*
>
< HTTP/1.1 302 Authenticate at this location
< Cache-Control: no-cache, no-store, must-revalidate
< Location: https://localhost/internal_forms_authentication/?targetId=2aa7575d-3234-4980-956c-2c6929c57b71
< Content-Length: 0
<

Nevertheless, this is still a good way to determine the state of a Qlik instance, because if it redirects using 302 Authenticate at this location it is likely that the server is not vulnerable to CVE-2023-48365.

An example response from a vulnerable server would return the JSON file:

> GET /resources/autogenerated/product-info.json?.ttf HTTP/1.1
> Host: localhost
> Accept: */*
>
< HTTP/1.1 200 OK
< Set-Cookie: X-Qlik-Session=893de431-1177-46aa-88c7-b95e28c5f103; Path=/; HttpOnly; SameSite=Lax; Secure
< Cache-Control: public, max-age=3600
< Transfer-Encoding: chunked
< Content-Type: application/json;charset=utf-8
< Expires: Tue, 16 Apr 2024 08:14:56 GMT
< Last-Modified: Fri, 04 Nov 2022 23:28:24 GMT
< Accept-Ranges: bytes
< ETag: 638032013040000000
< Server: Microsoft-HTTPAPI/2.0
< Date: Tue, 16 Apr 2024 07:14:55 GMT
< Age: 136
<
{"composition":{"contentHash":"89c9087978b3f026fb100267523b5204","senseId":"qliksenseserver:14.54.21","releaseLabel":"February 2022 Patch 12","originalClassName":"Composition","deprecatedProductVersion":"4.0.X","productName":"Qlik Sense","version":"14.54.21","copyrightYearRange":"1993-2022","deploymentType":"QlikSenseServer"},
<snipped>

We utilised Censys and Google BigQuery [⁶] to compile a list of potential Qlik Sense servers accessible on the internet and conducted a version scan against them. Subsequently, we extracted the Qlik release label from the JSON response to assess vulnerability to CVE-2023-48365.

Our vulnerability assessment for DoubleQlik / CVE-2023-48365 operated on the following criteria:

1. The release label corresponds to vulnerability statuses outlined in the original ZeroQlik and DoubleQlik vendor advisories [⁷,⁸].
2. The release label is designated as End of Support (EOS) by the vendor [⁹], such as “February 2019 Patch 5”.

We consider a server non-vulnerable if:

1. The release label date is post-November 2023, as the advisory states that “November 2023” is not affected.
2. The server responded with HTTP/1.1 302 Authenticate at this location.

Any other responses were disregarded as invalid Qlik server instances.

As of 17 April 2024, and as stated in the introduction of this blog, we have detected 5205 Qlik Servers on the Internet. Among them, 3143 servers are still at risk of DoubleQlik, indicating that 60% of all Qlik Servers online remain vulnerable.

Figure 2: Qlik Sense patch status for DoubleQlik CVE-2023-48365

The majority of vulnerable Qlik servers reside in the United States (396), trailed by Italy (280), Brazil (244), the Netherlands (241), and Germany (175).

Figure 3: Top 20 countries with servers vulnerable to DoubleQlik CVE-2023-48365

Identifying compromised Qlik Sense servers

Based on insights gathered from the Arctic Wolf blog and our own incident response engagements where the Cactus ransomware was observed, it’s evident that the Cactus ransomware group continues to redirect the output of executed commands to a True Type font file named qle.ttf, likely abbreviated for “qlik exploit”.

Below are a few examples of executed commands and their output redirection by the Cactus ransomware group:

whoami /all > ../Client/qmc/fonts/qle.ttf
quser > ../Client/qmc/fonts/qle.ttf

In addition to the qle.ttf file, we have also observed instances where qle.woff was used:

Figure 4: Directory listing with exploitation artefacts left by Cactus ransomware group

It’s important to note that these font files are not part of a default Qlik Sense server installation.

We discovered that files with a font file extension such as .ttf and .woff can be accessed without any authentication, regardless of whether the server is patched. This likely explains why the Cactus ransomware group opted to store command output in font files within the fonts directory, which in turn, also serves as a useful indicator of compromise.

Our scan for both font files, found a total of 122 servers with the indicator of compromise. The United States ranked highest in exploited servers with 49 online instances carrying the indicator of compromise, followed by Spain (13), Italy (11), the United Kingdom (8), Germany (7), and then Ireland and the Netherlands (6).

Figure 5: Top 20 countries with known compromised Qlik Sense servers

Out of the 122 compromised servers, 46 were not vulnerable anymore.

When the indicator of compromise artefact is present on a remote Qlik Sense server, it can imply various scenarios. Firstly, it may suggest that remote code execution was carried out on the server, followed by subsequent patching to address the vulnerability (if the server is not vulnerable anymore). Alternatively, its presence could signify a leftover artefact from a previous security incident or unauthorised access.

While the root cause for the presence of these files is hard to determine from the outside it still is a reliable indicator of compromise.

Responsible disclosure by the DIVD
We shared our fingerprints and scan data with the Dutch Institute of Vulnerability Disclosure (DIVD), who then proceeded to issue responsible disclosure notifications to the administrators of the Qlik Sense servers.

Call to action

Ensure the security of your Qlik Sense installations by checking your current version. If your software is still supported, apply the latest patches immediately. For systems that are at the end of support, consider upgrading or replacing them to maintain robust security.

Additionally, to enhance your defences, it’s recommended to avoid exposing these services to the entire internet. Implement IP whitelisting if public access is necessary, or better yet, make them accessible only through secure remote working solutions.

If you discover you’ve been running a vulnerable version, it’s crucial to contact your (external) security experts for a thorough check-up to confirm that no breaches have occurred. Taking these steps will help safeguard your data and infrastructure from potential threats.

References

1. https://cyberveilignederland.nl/actueel/persbericht-samenwerkingsverband-melissa-vindt-diverse-nederlandse-slachtoffers-van-ransomwaregroepering-cactus ︎
2. https://www.ncsc.nl/actueel/nieuws/2023/oktober/3/melissa-samenwerkingsverband-ransomwarebestrijding ︎
3. https://arcticwolf.com/resources/blog/qlik-sense-exploited-in-cactus-ransomware-campaign/ ︎
4. https://www.praetorian.com/blog/qlik-sense-technical-exploit/ ︎
5. https://www.praetorian.com/blog/doubleqlik-bypassing-the-original-fix-for-cve-2023-41265/ ︎
6. https://support.censys.io/hc/en-us/articles/360038759991-Google-BigQuery-Introduction ︎
7. https://community.qlik.com/t5/Official-Support-Articles/Critical-Security-fixes-for-Qlik-Sense-Enterprise-for-Windows/ta-p/2110801 ︎
8. https://community.qlik.com/t5/Official-Support-Articles/Critical-Security-fixes-for-Qlik-Sense-Enterprise-for-Windows/ta-p/2120325 ︎
9. https://community.qlik.com/t5/Product-Lifecycle/Qlik-Sense-Enterprise-on-Windows-Product-Lifecycle/ta-p/1826335 ︎

October 2022 Windows Update brought fixes for two interesting vulnerabilities, CVE-2022-38034 and CVE-2022-38045. They allowed a remote attacker to access various "local-only" RPC functions in Windows Workstation and Windows Server services respectively, bypassing these services' RPC security callbacks. These vulnerabilities were found by Ben Barnea and Stiv Kupchik of Akamai who published a detailed article and provided a proof-of-concept tool.

We missed this publication back in 2022 (probably being busy patching some other vulnerabilities), but once we found it we confirmed that some of the legacy Windows versions that we had security-adopted were affected and decided to provide patches for them.

The Vulnerability

The vulnerability stems from the fact that older Windows systems, but also current Windows systems with less than 3.5GB of RAM, pack two or more services into the same svchost.exe process. Apparently this can be a problem; in our case, it enables both Workstation and Server Service - which normally don't accept authentication requests - to accept authentication requests when bundled up with another service that does. When that happens, the previously (remotely) inaccessible functions from these services become remotely accessible because successful authentication gets cached and is subsequently looked up without additional security checks.

Microsoft's Patch

Microsoft's patch effectively disabled said caching for both services. Patched versions of wkssvc.dll and srvsvc.dll contain updated flags that are passed to the RpcServerRegisterIfEx function when these service are initialized. The flags that were previously 0x11 (RPC_IF_ALLOW_CALLBACKS_WITH_NO_AUTH | RPC_IF_AUTOLISTEN) have been replaced with 0x91 (RPC_IF_ALLOW_CALLBACKS_WITH_NO_AUTH | RPC_IF_AUTOLISTEN | RPC_IF_SEC_CACHE_PER_PROC).

Our Micropatch

We could patch these vulnerabilities in wkssvc.dll and srvsvc.dll in exactly the same way Microsoft did, but that would require users to restart Workstation and Server services for the modified flags to kick in. (Remember that Windows updates make you restart the computer anyway, but we have higher standards than that and want our patches to come in effect without a restart.)

Therefore, we decided to place our patches in rpcrt4.dll, which gets loaded in all RPC server processes and manages the cache and security callbacks for every Windows RPC interface. Our patch sits in the RPC_INTERFACE::DoSyncSecurityCallback function that processes the cached values and decides whether to call the security callback or use the cached result. It first checks if it's running in the Workstation or Server Service process, and if so, simply forces the security callback.

Here's the source code of our micropatch.

While working on this patch we noticed that the Workstation Service security callback behaved differently on different Windows versions. On Windows 10 and later, the security callback blocks functions with numbers ("opnums") between 8 and 11 from being executed remotely, which is exactly what CVE-2022-38034 bypasses. However, on older Windows versions like Windows 7 up to ESU 2 (2nd year of Extended Security Updates), these functions are not blocked from remote access at all. For our CVE-2022-38034 patch to even make sense on these older versions of Windows, we therefore first needed to add the missing security callback checks to wkssvc.dll.

We were curious about the origin of these security checks and did some digging across different wkssvc.dll versions. We found they were added to the Workstation Service some time before April 2021 on Windows 10, and sometime after January 2022 on Windows 7, but we were unable to find any CVE references associated with them. Our best guess is that they were added silently, first on Windows 10 and almost a year later also on Windows 7.

Our patch for this CVE-less vulnerability behaves the same as Microsoft's. First, we get the caller's binding data,  then we check the opnum of the called function and determine whether the user is local or not. If the called opnum is between 8 and 11 and the caller is not local, we fail the call with "access denied" error. 

Micropatch Availability

Micropatches were written for the following security-adopted versions of Windows with all available Windows Updates installed:

1. Windows 10 v2004 - fully updated
2. Windows 10 v1909 - fully updated
3. Windows 10 v1809 - fully updated
4. Windows 10 v1803 - fully updated
5. Windows 7 - fully updated with no ESU, ESU 1 or ESU 2
6. Windows Server 2008 R2 - fully updated with no ESU, ESU 1 or ESU 2

Vulnerabilities like these get discovered on a regular basis, and attackers know about them all. If you're using Windows that aren't receiving official security updates anymore, 0patch will make sure these vulnerabilities won't be exploited on your computers - and you won't even have to know or care about these things.

If you're new to 0patch, create a free account in 0patch Central, then install and register 0patch Agent from 0patch.com, and email [email protected] for a trial. Everything else will happen automatically. No computer reboot will be needed.

We would like to thank Ben Barnea and Stiv Kupchik of Akamai for sharing their analysis and proof-of-concept, which made it possible for us to create micropatches for these issues.

*Updated 2024-04-25 16:57 GMT with minor wording corrections regarding the targeting of other vendors.

ArcaneDoor is a campaign that is the latest example of state-sponsored actors targeting perimeter network devices from multiple vendors. Coveted by these actors, perimeter network devices are the perfect intrusion point for espionage-focused campaigns. As a critical path for data into and out of the network, these devices need to be routinely and promptly patched; using up-to-date hardware and software versions and configurations; and be closely monitored from a security perspective. Gaining a foothold on these devices allows an actor to directly pivot into an organization, reroute or modify traffic and monitor network communications. In the past two years, we have seen a dramatic and sustained increase in the targeting of these devices in areas such as telecommunications providers and energy sector organizations — critical infrastructure entities that are likely strategic targets of interest for many foreign governments.  

Cisco’s position as a leading global network infrastructure vendor gives Talos’ Intelligence and Interdiction team immense visibility into the general state of network hygiene. This also gives us uniquely positioned investigative capability into attacks of this nature. Early in 2024, a vigilant customer reached out to both Cisco’s Product Security Incident Response Team (PSIRT) and Cisco Talos to discuss security concerns with their Cisco Adaptive Security Appliances (ASA). PSIRT and Talos came together to launch an investigation to assist the customer. During that investigation, which eventually included several external intelligence partners and spanned several months, we identified a previously unknown actor now tracked as UAT4356 by Talos and STORM-1849 by the Microsoft Threat Intelligence Center. This actor utilized bespoke tooling that demonstrated a clear focus on espionage and an in-depth knowledge of the devices that they targeted, hallmarks of a sophisticated state-sponsored actor. 

UAT4356 deployed two backdoors as components of this campaign, “Line Runner” and “Line Dancer,” which were used collectively to conduct malicious actions on-target, which included configuration modification, reconnaissance, network traffic capture/exfiltration and potentially lateral movement.  

Critical Fixes Available 

Working with victims and intelligence partners, Cisco uncovered a sophisticated attack chain that was used to implant custom malware and execute commands across a small set of customers. While we have been unable to identify the initial attack vector, we have identified two vulnerabilities (CVE-2024-20353 and CVE-2024-20359), which we detail below. Customers are strongly advised to follow the guidance published in the security advisories discussed below.  

Further, network telemetry and information from intelligence partners indicate the actor is interested in — and potentially attacking — Microsoft Exchange servers and network devices from other vendors. Regardless of your network equipment provider, now is the time to ensure that the devices are properly patched, logging to a central, secure location, and are configured to have strong, multi-factor authentication (MFA). Additional recommendations specific to Cisco are available here.  

Timeline 

Cisco was initially alerted to suspicious activity on an ASA device in early 2024. The investigation that followed identified additional victims, all of which involved government networks globally. During the investigation, we identified actor-controlled infrastructure dating back to early November 2023, with most activity taking place between December 2023 and early January 2024. Further, we have identified evidence that suggests this capability was being tested and developed as early as July 2023.   

Cisco has identified two vulnerabilities that were abused in this campaign (CVE-2024-20353 and CVE-2024-20359). Patches for these vulnerabilities are detailed in the Cisco Security Advisories released today.

Initial Access 

We have not determined the initial access vector used in this campaign. We have not identified evidence of pre-authentication exploitation to date. Our investigation is ongoing, and we will provide updates, if necessary, in the security advisories or on this blog.

Line Dancer: In-Memory Implant Technical Details 

The malware implant has a couple of key components. The first is a memory-only implant, called “Line Dancer.” This implant is a memory-resident shellcode interpreter that enables adversaries to upload and execute arbitrary shellcode payloads.  

On a compromised ASA, the attackers submit shellcode via the host-scan-reply field, which is then parsed by the Line Dancer implant. Note that the use of this field does not indicate the exploitation of CVE-2018-0101 which was NOT used as a component of this campaign. The host-scan-reply field, typically used in later parts of the SSL VPN session establishment process, is processed by ASA devices configured for SSL VPN, IPsec IKEv2 VPN with “client-services" or HTTPS management access. The actor overrides the pointer to the default host-scan-reply code to instead point to the Line Dancer shellcode interpreter. This allows the actor to use POST requests to interact with the device without having to authenticate and interact directly through any traditional management interfaces. 

Line Dancer is used to execute commands on the compromised device. During our investigation, Talos was able to observe the threat actors using the Line Dancer malware implant to: 

• Disable syslog. 
• Run and exfiltrate the command show configuration. 
• Create and exfiltrate packet captures. 
• Execute CLI commands present in shellcode; this includes configuration mode commands and the ability to save them to memory (write mem). 
• Hook the crash dump process, which forces the device to skip the crash dump generation and jump directly to a device reboot. This is designed to evade forensic analysis, as the crash dump would contain evidence of compromise and provide additional forensic details to investigators. 
• Hook the AAA (Authentication, Authorization and Accounting) function to allow for a magic number authentication capability. When the attacker attempts to connect to the device using this magic number, they are able to establish a remote access VPN tunnel bypassing the configured AAA mechanisms. As an alternate form of access, a P12 blob is generated along with an associated certificate and exfiltrated to the actor along with a certificate-based tunnel configuration.  

Host-Scan-Reply hook overview 

In the Line Dancer implant’s process memory, we found a function (detailed below) that checks if a 32-byte token matches a pattern. If so, it base64-decodes the payload, copies it into the attacker's writable and executable memory region, and then calls the newly decoded function. Either way, it ends by calling processHostScanReply(). 

The function processHostScanReply() is normally accessed through a function pointer in the elementArray table, associated with the string host-scan-reply. In the captured memory, the entry that should point to processHostScanReply() now instead points to the attacker's function that decodes and runs its payload. Since this change is in the data section of memory, it doesn't show up in hashes/dumps of text. 
 
The attacker function that decodes and runs its payload has the following decompilation: 

Line Runner: Persistence Mechanism 

The threat actor maintains persistence utilizing a second, but persistent, backdoor called “Line Runner” on the compromised ASA device using functionality related to a legacy capability that allowed for the pre-loading of VPN clients and plugins on the device. At boot, the ASA is designed to look for the presence of a file on disk0: matching the Lua regular expression:

 ^client_bundle[%w_-]*%.zip$  

If the file exists, it will unzip it and execute the script csco_config.lua. Once processed, the ZIP file is deleted. This is assigned CVE-2024-20359 and more details are available in this Cisco Security Advisory.  

In at least one case, there is another vulnerability, CVE-2024-20353, that was abused by the actor to facilitate this process. The attackers were able to leverage this vulnerability to cause the target ASA device to reboot, triggering the unzipping and installing the second component of the threat actor’s malware implant, Line Runner. 

The threat actor’s ZIP file has the following files: 

The scripts in the zip file allow the threat actor to maintain a persistent HTTP-based Lua backdoor to the ASA, which survives across reboots and upgrades. Line Runner was observed being used by UAT4356 to retrieve information that was staged through the use of Line Dancer.  

csco_config.lua 

The csco_config.lua file is run at boot and makes the following modifications to the system: 
 
• Create disk0:/csco_config/97/webcontent/ if it doesn't already exist 
• Create disk0:/csco_config/97/webcontent/1515480F4B538B669648B17C02337098 from hash.txt 
• Append index.txt to disk0:/csco_config/97/webcontent/index_bp.ini and put the result in disk0:/csco_config/97/webcontent/index.ini 
• Move the original client_bundle.zip file to /run/lock/subsys/krbkdc6
• Prepend umtfc.txt to /etc/init.d/umountfs 
• Copy stgvdr.txt to /asa/scripts/lina_cs 
• Backup /asa/scripts/lina_exe_cs.sh to /asa/scripts/lina_exe_cs_bp.sh 
• Replace /asa/scripts/lina_exe_cs.sh with laecsnw.txt 
• Copy csco_config2.lua over csco_config.lua 
• Disable the importPlugin function for the next call only  

csco_config2.lua 

The csco_config2.lua file cleans up the modifications made by csco_config.lua (above) and removes itself. 

hash.txt 

Used as content for disk0:/csco_config/97/webcontent/1515480F4B538B669648B17C02337098. 

Intercepts HTTP requests to the ASA. The threat actor’s code looks for an HTTP request with a set of 32-character parameters that are victim-dependent. If they match, then the payload contained within one of these parameters is written to a Lua script and executed. This is the backdoor’s command and control mechanism. 

index.txt 

Adds webContent information so hash.txt is processed. 

laecsnw.txt 

Temporarily replaces /asa/scripts/lina_exe_cs.sh. 

Executes /asa/scripts/lina_cs as a background process (see below). Removes itself. Then restore the backup /asa/scripts/lina_exe_cs_bp.sh.  

stgvdr.txt 

Runs as /asa/scripts/lina_cs. 

After sleeping for 30 seconds, sets expected owner and times on /etc/init.d/umountfs. Removes the hash API endpoint, the index.ini, and either restores the backup index.ini or removes the webcontent directory entirely. Finally, removes itself.  

umtfc.txt

Prepended to /etc/init.d/unmountfs. 

The unmountfs script is called at shutdown to unmount the filesystems. The threat actor’s modifications perform the following functionality: 

• If disk0:/csco_config/97/webcontent/1515480F4B538B669648B17C02337098 exists, it removes it and index.ini. 
• Copy /run/lock/subsys/krbkdc6 to disk0:client_bundle_install.zip

This sets up the zipfile to be executed at the next boot, maintaining persistence. 

Forensic Recovery and Identification of Line Runner 

To identify the presence of Line Runner on an ASA, the following methods can be used. Note also that the device should be upgraded to a fixed version as identified in the first method. 

Method 1: 

After updating the device to a software release that contains the fix for CVE-2024-20359, a review of the contents of disk0: should be conducted. If a new file (e.g., “client_bundle_install.zip” or any other unusual .zip file) appears on disk0: following the update, this suggests that Line Runner was present on the device in question. Note that because the updated software is not vulnerable to CVE-2024-20359, Line Runner will no longer be active on the device. 

Method 2: 

To detect (and remove) Line Runner, the following series of commands will create an innocuous file with a .zip extension. Note that it will not create a valid zip file, but the file will still be read by the ASA at reboot. Upon execution of the following commands, if a new .zip file appears on disk0: following the reload, this suggests that Line Runner was present on the device in question. Deletion of the “client_bundle_install.zip” file will remove Line Runner. Note that the malicious ZIP containing the Line Runner functionality could have other names that fit the naming pattern outlined previously.  

If you discover a newly created .zip file, copy that file off the device using the copy command and contact [email protected] referencing CVE-2024-20359. Include the outputs of the dir disk0: and show version commands from the device and the .zip file extracted from the device. 

Anti-Forensics/Anti-Analysis Capabilities 

UAT4356 took clear and deliberate steps to attempt to prevent forensic capture of malicious artifacts. This tradecraft suggests a thorough understanding of the ASA itself and of the forensic actions commonly performed by Cisco for network device integrity validation. Additional steps were taken on a case-by-case basis to hide actions being taken on the device. These steps included hooking the AAA (Authentication, Authorization and Accounting) function of the device to allow the actor to bypass normal AAA operations. We also identified some instances where UAT4356 disabled logging to perform operations on or from the ASA and not have those operations or actions logged.  

Line Dancer appears to have been intentionally placed into a difficult-to-reach region of memory. In addition, it hooks into functions such as the core dump function, which is commonly used to collect information for debugging and forensic purposes, which were made in memory such that this function simply jumped to a reboot. This means that on reboot, Line Dancer itself would no longer be present and none of the collections present in the core dump function would have been executed, all resulting in a complete loss of debug information and memory-based forensic artifacts. 

Attribution  

As a part of our ongoing investigation, we have also conducted analysis on possible attribution of this activity. Our attribution assessment is based on the victimology, the significant level of tradecraft employed in terms of capability development and anti-forensic measures, and the identification and subsequent chaining together of 0-day vulnerabilities. For these reasons, we assess with high confidence that these actions were performed by a state-sponsored actor.

Recommendations 

There are some known indicators of compromise that customers can look for if they suspect they may have been targeted in this campaign. First, organizations should look for any flows to/from ASA devices to any of the IP addresses present in the IOC list provided at the bottom of this blog. This is one indication that further investigation is necessary. 

Additionally, organizations can issue the command show memory region | include lina to identify another indicator of compromise. If the output indicates more than one executable memory region (memory regions having r-xp permissions, see output examples), especially if one of these memory sections is exactly 0x1000 bytes, then this is a sign of potential tampering.   

Note that the earlier provided steps to identify the presence of Line Runner can still be followed even in the absence of more than one executable memory region as we have seen cases where Line Runner was present without Line Dancer being present. We still recommend following the steps to upgrade to a patched version even if customers believe that their device has not been compromised.  

Next, follow the steps detailed in the Cisco ASA Forensic Investigation Procedures for First Responders. When following these procedures first responders should NOT attempt to collect a core dump (Step 5) or reboot the device if they believe that the device has been compromised, based on the lina memory region output. The previous steps up to and including a collection of the memory text section should be followed. In addition, we have released some Snort signatures to detect the activity on the wire including access attempts. Signatures 63139, 62949, and 45575 have been released to detect the implants or associated behaviors. Please note that the device must be set up to decrypt TLS for these signatures to be effective. 

• CVE-2024-20353 (ASA DOS/Reboot) - 3:63139 
• ‘Line Runner’ – Persistence Mechanism Interaction – 3:62949 
• ‘Line Dancer’ – In-Memory Only Shellcode Interpreter Interaction – 3:45575 
• Note that this signature was originally built to detect an unrelated CVE but it also detects Line Dancer interaction 

If your organization does find connections to the provided actor IPs and the crash dump functionality has been altered, please open a case with Cisco TAC.  

UAT4356 Infrastructure 

Key components of the actor-controlled infrastructure used for this operation had an interesting overlap of SSL certificates which match the below pattern while also appearing as an ASA, during the same period, to external scanning engines such as Shodan and Censys as reported by the CPE data on the same port as the noted SSL certificate. The SSL certificate information suggests that the infrastructure is making use of an OpenConnect VPN Server (https://ocserv.openconnect-vpn.net) through which the actor appeared to be conducting actions on target. 

Certificate Pattern: 
:issuer = O=ocserv,CN=ocserv VPN 
:selfsigned = true 
:serial = 0000000000000000000000000000000000000002 
:subject = O=ocserv,CN=ocserv VPN 
:version = v3 

CPE identifiers:  
cpe:2.3:a:cisco:http:*:*:*:*:*:*::
cpe:2.3:h:cisco:adaptive_security_appliance:*:*:*:*:*:*:*:* 
cpe:2.3:o:cisco:adaptive_security_appliance_software:*:*:*:*:*:*:*:* 

MITRE TTPs 

This  threat demonstrates several techniques of the MITRE ATT&CK framework, most notably: 

• Line Runner persistence mechanism (T1037),  
• The reboot action via CVE-2024-20353 (T1653),  
• Base64 obfuscation (T1140),  
• Hooking of the processHostScanReply() function (T0874),  
• Disabling syslog and tampering with AAA (T1562-001), 
• Injection of code into AAA and Crash Dump processes (T1055)  
• Execution of CLI commands (T1059),  
• Bypassing of the AAA mechanism (T1556),  
• Removal of files after execution (T1070-004),  
• HTTP interception for C2 communications (T1557),  
• HTTP C2 (T1071-001),  
• HTTP C2 one-way backdoor (T1102-003),  
• Data exfiltration over C2 (T1041),  
• Network sniffing (T1040)  

Coverage 

Cisco Secure Firewall (formerly Next-Generation Firewall and Firepower NGFW) appliances such as Threat Defense Virtual, Adaptive Security Appliance and Meraki MX can detect malicious activity associated with this threat. 

Umbrella, Cisco's secure internet gateway (SIG) blocks devices from connecting to malicious IPs. Sign up for a free trial of Umbrella here. 

Additional protections with context to your specific environment and threat data are available from the Firewall Management Center. 

Open-source Snort Subscriber Rule Set customers can stay up to date by downloading the latest rule pack available for purchase on Snort.org. Snort SIDs for this threat are 45575, 62949 and 63139. 

Indicators of Compromise (IOCs)  

There are several known indicators of compromise that defenders can look for when assessing whether their ASA device has been compromised as a result of this attack, as outlined earlier in this post. For example, if any gaps in logging or any recent unexpected reboots are observed, this should be treated as suspicious activity that warrants further investigation. Also, below is a list of IP addresses we identified as having been used by UAT4356. Please note that some of these IPs are part of publicly known anonymization infrastructure and not directly controlled by the attackers themselves. If your organization does find connections to the provided actor IPs and the crash dump functionality has been altered, please open a case with Cisco TAC. 

Likely Actor-Controlled Infrastructure: 

192.36.57[.]181 
185.167.60[.]85 
185.227.111[.]17 
176.31.18[.]153 
172.105.90[.]154 
185.244.210[.]120 
45.86.163[.]224 
172.105.94[.]93 
213.156.138[.]77 
89.44.198[.]189 
45.77.52[.]253 
103.114.200[.]230 
212.193.2[.]48 
51.15.145[.]37 
89.44.198[.]196 
131.196.252[.]148 
213.156.138[.]78 
121.227.168[.]69 
213.156.138[.]68 
194.4.49[.]6 
185.244.210[.]65 
216.238.75[.]155  

Multi-Tenant Infrastructure: 

5.183.95[.]95 
45.63.119[.]131 
45.76.118[.]87 
45.77.54[.]14 
45.86.163[.]244 
45.128.134[.]189    
89.44.198[.]16 
96.44.159[.]46 
103.20.222[.]218 
103.27.132[.]69 
103.51.140[.]101 
103.119.3[.]230 
103.125.218[.]198 
104.156.232[.]22 
107.148.19[.]88 
107.172.16[.]208 
107.173.140[.]111 
121.37.174[.]139 
139.162.135[.]12 
149.28.166[.]244 
152.70.83[.]47 
154.22.235[.]13 
154.22.235[.]17 
154.39.142[.]47  
172.233.245[.]241 
185.123.101[.]250 
192.210.137[.]35  
194.32.78[.]183 
205.234.232[.]196  
207.148.74[.]250 
216.155.157[.]136 
216.238.66[.]251 
216.238.71[.]49 
216.238.72[.]201 
216.238.74[.]95 
216.238.81[.]149 
216.238.85[.]220 
216.238.86[.]24  

Acknowledgments  

Cisco would like to thank the following organizations for supporting this investigation: 

• Australian Signals Directorate’s Australian Cyber Security Centre 
• Black Lotus Labs at Lumen Technologies 
• Canadian Centre for Cyber Security, a part of the Communications Security Establishment 
• Microsoft Threat Intelligence Center 
• The UK's National Cyber Security Centre (NCSC) 
• U.S. Cybersecurity & Infrastructure Security Agency (CISA) 

The post Fortifying the Chain: A Proven Strategy for Supply Chain Defense appeared first on Horizon3.ai.

TL;DR (really?): Members of Distributed COM Users or Performance Log Users Groups can trigger from remote and relay the authentication of users connected on the target server, including Domain Controllers. #SilverPotato

Remember my previous article? My insatiable curiosity led me to explore the default DCOM permissions on Domain Controllers during a quiet evening…

Using some custom Powershell scripts, I produced an Excel sheet with all the information I needed.

You can’t imagine the shock I felt when I discovered these two Application Id’s

The first one, sppui with ID: {0868DC9B-D9A2-4f64-9362-133CEA201299}, seemed very interesting because it was impersonating the Interactive user. Combined with the permissions granted to Everyone for activating this application from remote, this could potentially lead to some unexpected privilege escalation, don’t you think?

The output of the DCOMCNFG tool confirmed my analysis:

But wait, this does not mean Everyone can activate this DCOM Application remotely. We have to look also at the default limits for Everyone:

Everyone can only activate and launch locally… but… there are these two interesting groups, Distributed COM Users and Performance Log Users who can launch and activate the application remotely:

Combined with Everyone’s permission this sounds really interesting! But before going further, what is this application sspui?

With the magic Oleview tool, we can get much more information:

This app has the following CLSID F87B28F1-DA9A-4F35-8EC0-800EFCF26B83 – SPPUIObjectInteractive Class, and runs as a Local Server :

slui.exe is related to the License Activation Service and exposes some interfaces:

At first glance, the methods implemented seem not very interesting from an Attacker perspective.

However, we have this DCOM object running in the context of the interactive user, accessible remotely by members of these two groups. So, why not attempt coercing authentication using our *potato exploit? If successful, we could intercept the authentication of the user connected to the Domain Controller, who should theoretically be a Domain Admin, correct ?

This is very similar to what I did in ADCCoercePotato, except for the fact that we may need to implement also the cross-session activation if we want to specify a specific session ID where the user is logged in.

I won’t go too much into the details; @splinter_code and I have discussed this argument so many times

The key point is that there are two authentication processes: the first occurs during the oxid resolve call, while the second takes place when the victim attempts to contact the malicious endpoint.

First AUTH

I obviously tried the first one, and without too much effort, was able to trigger and intercept the NTLM authentication of a Domain Admin connected to the target Domain Controller.

For testing purposes, I impersonated my user “simple”, a regular domain user and member of the “Performance Log Users” domain group:

I used my new “SilverPotato” tool, a modified version of ADCSCoercePotato:

In this case, with -m, I specified the IP address of the target domain controller, and with -k, the IP of the Linux box where the socat redirector and ntlmrelayx were running:

And yes, it worked! I got the authentication of Administrator connected on the first session (I did not specify the session ID).

I decided to relay the authentication to the SMB service of the ADCS server (but it’s just an example…), which by default has no signing enabled, and dumped the local SAM database:

With the NT hash of the local Administrator, I could access the ADCS Server via Pass The Hash, backup the Private/Public key of the CA, and the get CRL configuration.

Side note: Of course, there are other methods to achieve remote code execution on the target server. For instance, I utilized ntlmrelay to copy my malicious wbemcomn.dll file with a reverse shell into the c:\windows\system32\wbem directory. This file was subsequently loaded under different conditions, granting me a shell with SYSTEM, Network Service, or logged-in User privileges

After this, with ForgeCert tool, I was able to request a certificate on behalf Domain Administrator with the backup file of the CA.

Finally, request a TGT with Rubeus and logon to the Domain Controller as Administrator

second auth

Afterward, I attempted to exploit the second authentication, which is more or less what we implemented in our RemotePotato0.

However, to my surprise, the resulting impersonation level in this case was limited to Identify, which is useless against SMB or HTTP, and unusable against LDAP/LDAPS because of the sign flag…

Otherwise, it could have presented a great opportunity to use Kerberos relay instead of NTLM, given that the Service Principal Name (SPN) was within the attacker’s control.

kerberos relay in first auth?

In theory, you could specify the Service Principal Name (SPN) in the first call in the security bindings strings of the “dualstring” array of the Marshalled Interface Pointer:

typedef struct tagSECURITYBINDING 
{
    unsigned short    wAuthnSvc;     // Must not be 0
    unsigned short    wAuthzSvc;     // Must not be 0
    unsigned short    aPrincName;    // NULL terminated
} SECURITYBINDING

I specified the SPN with the -y switch:

But my tests were unsuccessful, I always got back the SPN: RPCSS/IP in the NTLM3 message:

A few days ago, James Forshaw pointed out to me the potential for Kerberos relay via OXID resolving, by exploiting the marshaled target info trick detailed in his post under the “Marshaled Target Information SPN” section.

I attempted some tests but quickly gave up, using the excuse that I’m just too lazy .. so I’ll leave it up to you!

conclusion

At this point, I know I have to answer the fateful question: Did you report this to MSRC?

Obviously, yes! I’ll spare you the disclosure timeline. In short, MSRC confirmed the vulnerability and initially marked it as a critical fix. However, about a month later, they downgraded it to moderate severity. Their final verdict was: After careful investigation, this case has been assessed as moderate severity and does not meet MSRC’s bar for immediate servicing.

So, I feel free to publish this finding

I’m not going to release the source code for now, but crafting your own should be a breeze, wouldn’t you agree?

This “vulnerability” has been probably around for years, and it’s surprising that nobody has made it public.

So how dangerous is it?

Hard to say, especially since membership in groups like “Distributed COM Users” and “Performance Log Users” isn’t exactly commonplace, especially domain-wide. Also, the “Distributed COM Users” group is sometimes considered a tier 0 asset

But think about it: the ability to coerce and relay the (NTLM) authentication of highly privileged accounts from remote, is incredibly risky. It’s another valid reason to include privileged accounts in the Protected Users group!

Another point to consider is that this method applies to the local “Distributed COM Users” and “Performance Log Users” groups too. So, it really depends on who is logged into the server at the time…

I would recommend carefully reviewing the memberships of these and until MS won’t fix this vulnerability, definitely consider these groups tier 0!

What’s next after SilverPotato? Well, there’s another interesting one, but this was classified as an Important Privilege Escalation so I have to wait for the fix…

Last but not least, as usual, thanks to James Forshaw @tiraniddo and Antonio Cocomazzi @splinter_code for their precious help.

That’s all

Infromations Web Application Security

install :

sudo apt install python3 python3-pip

pip3 install termcolor

pip3 install google

pip3 install optioncomplete

pip3 install bs4


pip3 install prettytable

git clone https://github.com/Matrix07ksa/HackerInfo/

cd HackerInfo

chmod +x HackerInfo

./HackerInfo -h

python3 HackerInfo.py -d www.facebook.com -f pdf 
[+] <-- Running Domain_filter_File ....-->
[+] <-- Searching  [www.facebook.com] Files [pdf] ....-->
https://www.facebook.com/gms_hub/share/dcvsda_wf.pdf
https://www.facebook.com/gms_hub/share/facebook_groups_for_pages.pdf
https://www.facebook.com/gms_hub/share/videorequirementschart.pdf
https://www.facebook.com/gms_hub/share/fundraise-on-facebook_hi_in.pdf
https://www.facebook.com/gms_hub/share/bidding-strategy_decision-tree_en_us.pdf
https://www.facebook.com/gms_hub/share/fundraise-on-facebook_es_la.pdf
https://www.facebook.com/gms_hub/share/fundraise-on-facebook_ar.pdf
https://www.facebook.com/gms_hub/share/fundraise-on-facebook_ur_pk.pdf
https://www.facebook.com/gms_hub/share/fundraise-on-facebook_cs_cz.pdf
https://www.facebook.com/gms_hub/share/fundraise-on-facebook_it_it.pdf
https://www.facebook.com/gms_hub/share/fundraise-on-facebook_pl_pl.pdf
h   ttps://www.facebook.com/gms_hub/share/fundraise-on-facebook_nl.pdf
https://www.facebook.com/gms_hub/share/fundraise-on-facebook_pt_br.pdf
https://www.facebook.com/gms_hub/share/creative-best-practices_id_id.pdf
https://www.facebook.com/gms_hub/share/creative-best-practices_fr_fr.pdf
https://www.facebook.com/gms_hub/share/fundraise-on-facebook_tr_tr.pdf
https://www.facebook.com/gms_hub/share/creative-best-practices_hi_in.pdf
https://www.facebook.com/rsrc.php/yA/r/AVye1Rrg376.pdf
https://www.facebook.com/gms_hub/share/creative-best-practices_ur_pk.pdf
https://www.facebook.com/gms_hub/share/creative-best-practices_nl_nl.pdf
https://www.facebook.com/gms_hub/share/creative-best-practices_de_de.pdf
https://www.facebook.com/gms_hub/share/fundraise-on-facebook_de_de.pdf
https://www.facebook.com/gms_hub/share/creative-best-practices_cs_cz.pdf
https://www.facebook.com/gms_hub/share/fundraise-on-facebook_sk_sk.pdf
https://www.facebook.com/gms   _hub/share/creative-best-practices_japanese_jp.pdf
#####################[Finshid]########################

Usage:

Library install hackinfo:

sudo python setup.py install
pip3 install hackinfo

Free to use IOC feed for various tools/malware. It started out for just C2 tools but has morphed into tracking infostealers and botnets as well. It uses shodan.io/">Shodan searches to collect the IPs. The most recent collection is always stored in data; the IPs are broken down by tool and there is an all.txt.

The feed should update daily. Actively working on making the backend more reliable

Honorable Mentions

Many of the Shodan queries have been sourced from other CTI researchers:

• BushidoToken
• Michael Koczwara
• ViriBack
• Gi7W0rm
• @Glacius_

Huge shoutout to them!

Thanks to BertJanCyber for creating the KQL query for ingesting this feed

And finally, thanks to Y_nexro for creating C2Live in order to visualize the data

What do I track?

• C2's
  • Cobalt Strike
  • Metasploit Framework
  • Covenant
  • Mythic
  • Brute Ratel C4
  • Posh
  • Sliver
  • Deimos
  • PANDA
  • NimPlant C2
  • Havoc C2
  • Caldera
  • Empire
  • Ares
• Malware
  • AcidRain Stealer
  • Misha Stealer (AKA Grand Misha)
  • Patriot Stealer
  • RAXNET Bitcoin Stealer
  • Titan Stealer
  • Collector Stealer
  • Mystic Stealer
  • Gotham Stealer
  • Meduza Stealer
  • Quasar RAT
  • ShadowPad
  • AsyncRAT
  • DcRat
  • BitRAT
  • DarkComet Trojan
  • XtremeRAT Trojan
  • NanoCore RAT Trojan
  • Gh0st RAT Trojan
  • DarkTrack RAT Trojan
  • njRAT Trojan
  • Remcos Pro RAT Trojan
  • Poison Ivy Trojan
  • Orcus RAT Trojan
  • ZeroAccess Trojan
  • HOOKBOT Trojan
• Tools
  • XMRig Monero Cryptominer
  • GoPhish
• Botnets
  • 7777 Botnet

Running Locally

If you want to host a private version, put your Shodan API key in an environment variable called SHODAN_API_KEY

echo SHODAN_API_KEY=API_KEY >> ~/.bashrc
bash
python3 -m pip install -r requirements.txt
python3 tracker.py

Contributing

I encourage opening an issue/PR if you know of any additional Shodan searches for identifying adversary infrastructure. I will not set any hard guidelines around what can be submitted, just know, fidelity is paramount (high true/false positive ratio is the focus).

References

• Hunting C2 with Shodan by Michael Koczwara
• Hunting Cobalt Strike C2 with Shodan by Michael Koczwara
• https://twitter.com/MichalKoczwara/status/1591750513238118401?cxt=HHwWgsDUiZGqhJcsAAAA
• BushidoToken's OSINT-SearchOperators
• https://twitter.com/MichalKoczwara/status/1641119242618650653
• https://twitter.com/MichalKoczwara/status/1641676761283850241
• https://twitter.com/_montysecurity/status/1643164749599834112
• https://twitter.com/ViriBack/status/1713714868564394336
• https://gi7w0rm.medium.com/the-curious-case-of-the-7777-botnet-86e3464c3ffd
• https://twitter.com/Glacius_/status/1731699013873799209

(MS16-002, CVE-2016-0003)

Specially crafted Javascript inside an HTML page can trigger a type confusion bug in Microsoft Edge that allows accessing a C++ object as if it was a BSTR string. This can result in information disclosure, such as allowing an attacker to determine the value of pointers to other objects and/or functions. This information can be used to bypass ASLR mitigations. It may also be possible to modify arbitrary memory and achieve remote code execution, but this was not investigated.

A specially crafted style sheet inside an HTML page can trigger a NULL pointer dereference in Microsoft Internet Explorer 10 and 11. The pointer in question is assumed to point to a function, and the code attempts to use it to execute this function, which normally leads to an access violation when attempting to execute unmapped memory at address 0. In some cases, Control Flow Guard (CFG) will attempt to check if the address is a valid indirect call target. Because of the way CFG is implemented, this can lead to a read access violation in unmapped memory at a seemingly arbitrary address.

A specially crafted Javascript inside an HTML page can trigger a use-after-free bug in Tree::ANode::IsInTree or a breakpoint in Abandonment::InduceAbandonment in Microsoft Edge. The use-after-free bug is mitigated by MemGC: if MemGC is enabled (which it is by default) the memory is never freed. This effectively prevents exploitation of the issue. The Abandonment appears to be triggered by a stack exhaustion bug; the Javascript creates a loop where an event handler triggers a new event, which in turn triggers the event handler, etc.. This consumes a stack space until there is no more stack available. Edge does appear to be able to handle such a situation gracefully under certain conditions, but not all. It is easy to avoid those conditions to force triggering the Abandonment.

The interesting thing is that this indicates that the assumption that "hitting Abandonment means a bug is not a security issue" may not be correct in all cases.

A specially crafted Javascript inside an HTML page can trigger a use-after-free bug in the CTreePosGap::PartitionPointers function of edgehtml.dll in Microsoft Edge. This use-after-free bug is mitigated by MemGC by default: with MemGC enabled the memory is never actually freed. This mitigation is considered sufficient to make this a non-security issue as explained by Microsoft SWIAT in their blog post Triaging the exploitability of IE/Edge crashes.

Since this is not considered a security issue, I have the opportunity to share details about the issue with you before the issue has been fixed. And since Microsoft are unlikely to provide a fix for this issue on short notice, you should be able to reproduce this issue for some time after publication of this post. I will try to explain how I analyzed this issue using BugId and EdgeDbg, so that you can reproduce what I did and see for yourself.

While working independently has many advantages, it does have one major drawback: no one to bounce ideas off or help you solve problems. So, in order to address this, I am now looking for opportunities to work closer with other researchers again.

(MS16-063, CVE-2016-0199)

With MS16-063 Microsoft has patched CVE-2016-0199: a memory corruption bug in the garbage collector of the JavaScript engine used in Internet Explorer 11. By exploiting this vulnerability, a website can causes this garbage collector to handle some data in memory as if it was an object, when in fact it contains data for another type of value, such as a string or number. The garbage collector code will use this data as a virtual function table (vftable) in order to make a virtual function call. An attacker has enough control over this data to allow execution of arbitrary code.

Software components such as memory managers often use magic values to mark memory as having a certain state. These magic values have often (but not always) been chosen to coincide with addresses that fall outside of the user-land address space on 32-bit versions of the Operating System. This ensures that if a vulnerability in the software allows an attacker to get the code to use such a value as a pointer, this results in an access violation. However, on 64-bit architectures the entire 32-bit address space can be used for user-land allocations, allowing an attacker to allocate memory at all the addresses commonly used as magic values and exploit such a vulnerability.

In my previous blog post I wrote about "magic values" that were originally chosen to help mitigate exploitation of memory corruption flaws and how this mitigation could potentially be bypassed on 64-bit Operating Systems, specifically Windows. In this blog post, I will explain how to create a heap spray (of sorts) that can be used to allocate memory in the relevant address space range and fill it with arbitrary data for use in exploiting such a vulnerability.

(MS14-056, CVE-2014-4141)

A specially crafted web-page can cause Microsoft Internet Explorer 9 to reallocate a memory buffer in order to grow it in size. The original buffer will be copied to newly allocated memory and then freed. The code continues to use the freed copy of the buffer.

(The fix and CVE number for this bug are not known)

A specially crafted web-page can cause Microsoft Internet Explorer 11 to free a memory block that contains information about an image. The code continues to use the data in freed memory block immediately after freeing it. It does not appear that there is enough time between the free and reuse to exploit this issue.

(The fix and CVE number for this bug are not known)

A specially crafted web-page can cause Microsoft Internet Explorer 10 to read data out-of-bounds. This issue was fixed before I was able to analyze it in detail, hence I did not determine exactly what the root cause was.

(The fix and CVE number for this bug are not known)

A specially crafted web-page can cause Microsoft Internet Explorer 9 to access data before the start of a memory block. An attack that is able to control what is stored before this memory block may be able to disclose information from memory or execute arbitrary code.