Introduction Windows 10 is an incredibly feature rich Operating System (OS).  In the last four years, the innovative folks at Microsoft have continued to introduce and expand functionality as well as improve and integrate security features in its flagship OS.  On the second Tuesday of each month, many of us that live in the Windows […]

[*] Introduction .NET Core is an open-source, cross-platform framework for building and running applications.  The framework was introduced in 2014 as the (eventual) successor to the ever-popular .NET Framework. .NET Core runs on Windows, *Nix, and MacOS operating systems. The .NET Core management tool, DotNet (dotnet.exe), potentially offers an untapped attack surface on Windows when […]

Introduction Last week, I presented COM Under The Radar: Circumventing Application Control Solutions at BsidesCharm 2019.  In the presentation, I briefly discussed COM and highlighted a few techniques for bypassing Windows application control solutions.  One of those techniques takes advantage of an issue with catalog hygiene where old code often remains signed in updated versions […]

Introduction Greetings, Everyone!  It has been several months since I’ve blogged, so it seems fitting to start the New Year off with a post about two topics that I thoroughly enjoy exploring: Application Control/Application Whitelisting (AWL) and the Component Object Model (COM).  As the title suggests, I stumbled upon a technique for bypassing Microsoft Application […]

TL;DR There are several ways that attackers can leverage COM hijacking to influence evasive loading and hidden persistence.  A few examples include CLSID (sub)key abandonment referencing, key overriding, and key linking. There are several programs and utilities that can invoke COM registry payloads including Rundll32.exe, Xwizard.exe, Verclsid.exe, Mmc.exe, and the Task Scheduler.  In the traditional […]

TL;DR An Office XML (.xml) document can call a remote XSL stylesheet over SMB.  If this occurs against an attacker controlled server, the net-NTLM authentication hash (challenge/response) of that user is revealed.  Operationally, an attacker could crack this offline or leverage a relay technique for remote command execution (if privileged and on-net).  There are possible […]

TL;DR Vendors are notorious for including and/or leaving behind Registry artifacts that could potentially be abused by attackers for lateral movement, evasion, bypass, and persistence. CLSIDs subkeys (LocalServer32 and InprocServer32) can be enumerated to discover abandoned binary references. Interestingly, CLSIDs can be called (‘invoked’) with this command: rundll32.exe -sta {CLSID} Defensive recommendations – clean up […]

TL;DR This post discusses an alternate DCOM lateral movement discovery and payload execution method.  The primary gist is to locate DCOM registry key/values that point to the path of a binary on the ‘remote’ machine that does not exist.  This example method is likely to work if mobsync.exe is not in \\target\admin$\system32\, which is default […]