Our colleagues over at Core Security have been doing great things with Cobalt Strike, making use of it in their own engagements. They wrote up this post on creating Cobalt Strike Beacon Object Files using the MinGW compiler on Linux. It covers several ideas and best practices that will increase the quality of your BOFs. […]
Read More… from Writing Beacon Object Files: Flexible, Stealthy, and Compatible
The User Defined Reflective Loader (UDRL) was first introduced in Cobalt Strike 4.4. to allow the creation and use of a custom reflective loader. This quickly took off by the community and its limits were pushed. Updates were made in 4.5 to help address some of these limits. Updates Increased Size A new hook BEACON_DLL_SIZE […]
Read More… from User Defined Reflective Loader (UDRL) Update in Cobalt Strike 4.5
The Sleep Mask Kit was first introduced in Cobalt Strike 4.4 to allow users to modify how the sleep mask function looks in memory in order to defeat static signatures that identified Beacon. This quickly took off in the community and its limits were pushed. Updates were made in 4.5 to help address some of these limits. Licensed users can download the updated kit from […]
A complementary strategy to the Host Rotation Strategy was introduced to Cobalt Strike 4.5. The max retry strategy was added to HTTP, HTTPS, and DNS beacon listeners. A max retry strategy allows a beacon to exit after a specified failure count. As the failure count increases, sleep is adjusted to a specified value. By default, […]
Read More… from A Deeper Look Into the Max Retry Strategy Option
Process injection is a core component to Cobalt Strike post exploitation. Until now, the option was to use a built-in injection technique using fork&run. This has been great for stability, but does come at the cost of OPSEC. Cobalt Strike 4.5 now supports two new Aggressor Script hooks: PROCESS_INJECT_SPAWN and PROCESS_INJECT_EXPLICIT. These hooks allow a user to define how the fork&run and explicit injection techniques are implemented when executing post-exploitation […]
Read More… from Process Injection Update in Cobalt Strike 4.5
Cobalt Strike 4.5 is now available. This release sees new options for process injection, updates to the sleep mask and UDRL kits, evasion improvements and a command history update along with other, smaller changes. Security Updates Before getting into the details of the release, I just wanted to impress upon you how seriously we take […]
Read More… from Cobalt Strike 4.5: Fork&Run – you’re “history”
We will be making some changes to the Cobalt Strike infrastructure in late November/early December. We are not anticipating any downtime but we wanted to make you aware of what is changing and when. TLS certificate updates The current TLS certificates for www.cobaltstrike.com and verify.cobaltstrike.com both expire on 6th December. The certificates will be updated […]
Motivation It is known that dumping Windows credentials is a technique often utilized for everyday attacks by adversaries and, consequently, Red Teamers. This process has been out there for several years and is well documented by MITRE under the T1003.001 technique. Sometimes, when conducting a Red Team engagement, there may be some limitations when trying […]
DLL attacks (hijacking, proxying, etc) are a challenge defenders must face. They can be leveraged in a Red Team engagement to help measure these defenses. Have you used this technique? In this post, I’ll walk through an example of adding a DLL proxy to beacon.dll for use in a DLL Proxy attack. What is a […]
This project started after seeing how the user community tweaks and tunes Cobalt Strike. I was inspired by @BinaryFaultline and @Mcgigglez16 in their project https://github.com/emcghee/PayloadAutomation and blog post http://blog.redxorblue.com/2021/06/introducing-striker-and-payload.html. They created a clever way to interact with a teamserver without the GUI. Before I get too far, I’ll touch on Aggressor scripting and the Sleep […]