Cobalt Strike 4.10.1 is now available. This is an out of band update to fix issues that were discovered in Cobalt Strike 4.10 that we felt should be fixed before the next release. This update does not affect the 4.11 release which is well underway and due to ship in early 2025. Mutiple Team Server […]
The UDRL and the Sleepmask are key components of Cobalt Strike’s evasion strategy, yet historically they have not worked well together. For example, prior to CS 4.10, Beacon statically calculated its location in memory using a combination of its base address and its section table. This calculation was then modified depending on the contents of […]
Read More… from Revisiting the UDRL Part 3: Beacon User Data
Cobalt Strike 4.10 is now available. This release introduces BeaconGate, the Postex Kit, and Sleepmask-VS. In addition, we have overhauled the Sleepmask API, refreshed the Jobs UI, added new BOF APIs, added support for hot swapping C2 hosts, and more. This has been a longer release cycle than in previous releases to allow us to […]
This is a joint blog written by William Burgess (@joehowwolf) and Henri Nurmi (@HenriNurmi). In our ‘Cobalt Strike and YARA: Can I Have Your Signature?’ blog post, we highlighted that the sleep mask is a common target for in-memory YARA signatures. In that post we recommended using the evasive sleep mask option to scramble the […]
Cobalt Strike 4.9.1 is now available. This is an out of band update to fix an issue that was discovered in the 4.9 release that we felt would negatively impact customers as they start to roll out the release and for which there is no straightforward workaround. We also took the opportunity to address a […]
Cobalt Strike 4.9 is now available. This release sees an overhaul to Cobalt Strike’s post exploitation capabilities to support user defined reflective loaders (UDRLs), the ability to export Beacon without a reflective loader which adds official support for prepend-style UDRLs, support for callbacks in a number of built-in functions, a new in-Beacon data store and […]
This is the second installment in a series revisiting the User-Defined Reflective Loader (UDRL). In part one, we aimed to simplify the development and debugging of custom loaders and introduced the User-Defined Reflective Loader Visual Studio (UDRL-VS) template. In this installment, we’ll build upon the original UDRL-VS loader and explore how to apply our own […]
Read More… from Revisiting the User-Defined Reflective Loader Part 2: Obfuscation and Masking
This is a joint blog written by the Cobalt Strike and Outflank teams. It is also available on the Outflank site. Over the past few months there has been increasing collaboration and knowledge sharing internally between the Cobalt Strike and Outflank R&D teams. We are excited about the innovation opportunities made possible by this teamwork and […]
Read More… from Cobalt Strike and Outflank Security Tooling: Friends in Evasive Places
I blogged about the Cobalt Strike roadmap in March last year and while the fundamental tenets of our approach to R&D remain unaltered, a lot has changed behind the scenes over the past year or so. I try to engage with our customers on various platforms and over the past few months, I’ve been asked […]
Read More… from Cobalt Strike 2023 Roadmap and Strategy Update
This blog post accompanies a new addition to the Arsenal Kit – The User-Defined Reflective Loader Visual Studio (UDRL-VS). Over the past few months, we have received a lot of feedback from our users that whilst the flexibility of the UDRL is great, there is not enough information/example code to get the most out of […]
Read More… from Revisiting the User-Defined Reflective Loader Part 1: Simplifying Development