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Before yesterdayXPN InfoSec Blog

LAPS 2.0 Internals

13 August 2023 at 10:03
This year, LAPS 2.0 was released by Microsoft, and thankfully it now comes built-in to Windows. This time it comes ready for use with Active Directory, as well as being supported in Azure AD aka Entra ID. In this post, we’ll look at how LAPS 2.0 for Active Directory works under the hood, so you can make those fresh recommendations to your clients, and prepare yourself for the inevitable question... β€œBut we just deployed LAPS.. what does LAPS 2.0 do differently?!”.

PNG Steganography from First Principles

9 August 2023 at 10:03
Steganography is experiencing a revival as a wrapper for delivering payloads. In this post we'll go back to basics and show just how steganography can be applied to a PNG image using the common least significant bit (LSB) encoding technique. No magic... just raw information... and a little C++.

Building a Custom Mach-O Memory Loader for macOS - Part 1

4 February 2023 at 10:03
In this blog we'll look at what it takes to construct an in-memory loader for Mach-O bundles within MacOS Ventura without using dyld. We'll walk though the lower-level details of what makes up a Mach-O file, how dyld processes load commands to map areas into memory, and how we can emulate this to avoid writing payloads to disk.

Restoring Dyld Memory Loading

14 January 2023 at 12:03
Up until recently, we've enjoyed in-memory loading of Mach-O bundles courtesy of dyld and its NSCreateObjectFileImageFromMemory/NSLinkModule API methods. And while these methods still exist today, there is a key difference.. memory modules are now persisted to disk. So in this post we'll take a look at just what was changed in dyld, and see what we can do to restore this functionality... hopefully keeping our warez in memory for a little longer.

g_CiOptions in a Virtualized World

15 May 2022 at 06:43
With the leaking of code signing certificates and exploits for vulnerable drivers becoming common occurrences, adversaries are adopting the kernel as their new playground. And with Microsoft making technologies like Virtualization Based Security (VBS) and Hypervisor Code Integrity (HVCI) available, I wanted to take some time to understand just how vulnerable endpoints are when faced with an attacker set on escaping to Ring-0.


11 April 2022 at 03:00
In this post, we'll dig into just how SMB over QUIC works, answer some of the immediate questions around which attacks are feasible, and show how we can repurpose some existing tooling to capture NTLM handshakes.

Object Overloading

15 February 2022 at 20:01
In this post we are going to look at one such technique that I thought was cool while playing around with the Windows Object Manager, and which should allow us to load an arbitrary DLL of our creation into a Windows process during initial execution, something that I've been calling "Object Overloading" for reasons which will hopefully become apparent in this post.

Azure Application Proxy C2

24 April 2021 at 13:01
In this post, we are going to look at the Application Proxy protocol, how it works, and show how we can recreate enough functionality to allow us to create a custom inbound proxy into a client environment for our C2 traffic.

Tailoring Cobalt Strike on Target

4 February 2021 at 14:16
We've all been there, you've completed your initial recon, sent in your emails to gather those leaked HTTP headers, spent an age configuring your malleable profile to be just right, set up your CDNs and spun up your redirectors. Then it's time, you send in your email aaaaaand... nothing.

Bring Your Own VM - Mac Edition

28 December 2020 at 10:53
For a while I've wanted to explore the concept of leveraging a virtual machine on target during an engagement. The thought of having implant logic self-contained and running under a different OS to the base seems pretty interesting. But more so, I've been curious as to just how far traditional AV and EDR can go to detect malicious activity when running from a different virtual environment. While this is a nice idea, the issues with creating this type of malware are obvious, with increased comple...

The .NET Export Portal

24 November 2020 at 09:10
While working on some tooling recently I revisited the topic of .NET unmanaged exports and wanted to know just why this works in the way that it does. After all, by now we've all seen the COM calls required to spin up the CLR, so what makes unmanaged exports so special?