Introduction Over the span of the previous two blog posts in the series, I showed why the majority of Cobalt Strike (CS) BOFs are incompatible with Brute Ratel C4 (BRC4) and what you can do about it. I also presented CS2BR itself: it's a tool that makes patching BOFs to be compatible with BRC4 a … Continue reading Introducing CS2BR pt. III – Knees deep in Binary
Introduction In the previous post of this series we showed why Brute Ratel C4 (BRC4) isn't able to execute most BOFs that use the de-facto BOF API standard by Cobalt Strike (CS): BRC4 implements their own BOF API which isn't compatible with the CS BOF API. Then we also outlined an approach to solve this … Continue reading Introducing CS2BR pt. II – One tool to port them all
If you know all about CS, BRC4 and BOFs you might want to skip this introduction and get right into the problem statement. You can also jump right to the solution. Introduction When we conduct Red Team assessments at NVISO, we employ a wide variety of proprietary and open source tools. One central component in … Continue reading Introducing CS2BR pt. I – How we enabled Brute Ratel Badgers to run Cobalt Strike BOFs
It's time for the season finale. In this post we explore several bypasses but also look at some mistakes made along the way. 1. From zero to hero: a quick recap As promised in part 8, I spent some time converting the application to disable Driver Signature Enforcement (DSE) into a Beacon Object File (BOF) … Continue reading Kernel Karnage – Part 9 (Finishing Touches)
When life gives you exploits, you turn them into Beacon Object Files. 1. Back to BOFs I never thought I would say this, but after spending so much time in kernel land, it’s almost as if developing kernel functionality is easier than writing user land applications, especially when they need to fly under the radar. … Continue reading Kernel Karnage – Part 8 (Getting Around DSE)
Previously, we have already published Sander's (@cerbersec) internship testimony. Since this post does not really contain any juicy technical details and Sander has done a terrific job putting together a walkthrough of his process, we thought it would be a waste not to highlight his previous posts again. In Part 1, Sander explains how he … Continue reading All aboard the internship – whispering past defenses and sailing into kernel space
