The source code for the widely-used Cobalt Strike post-exploitation toolkit has allegedly been leaked online in a GitHub repository.
Cobalt Strike is a legitimate penetration testing toolkit that allows attackers to deploy “beacons” on compromised devices to remotely “create shells, execute PowerShell scripts, perform privilege escalation, or spawn a new session to create a listener on the victim system.”
Cobalt Strike is an immensely popular tool among threat actors who use cracked versions to gain persistent remote access to a compromised network. This tool is commonly seen used during ransomware attacks.
Twelve days ago, a repository was created on GitHub that contains what appears to be the source code for Cobalt Strike 4.0.
Based on the ‘src/main/resources/about.html’ file, this source code is for Cobalt Strike 4.0 released on December 5th, 2019.
Advanced Intel’s Vitali Kremez, who examined the source code, told BleepingComputer that he believes the Java code was manually decompiled. The person then fixed any dependencies and removed the license check, so that it could be compiled.
Even though it is not the original source code, it is enough to be of serious concern to security professionals.
“The possible re-compiled source code exposure of the “2019” Cobalt Strike 4.0 version has significant consequences for all defenders as it removes barriers of entry to obtaining the tool and essentially makes its easy for the crime groups to procure and modify code as needed on the fly.”
“The leak of the offensive tool opens the door for the additional crime actor enhancement of the tooling as it happens with the many malware tool leaks such as for Zeus 18.104.22.168. leak and TinyNuke one as they continuously re-used and updated by the crimewave goops and live their own “life” after the leak,” Kremez told BleepingComputer in a conversation.
BleepingComputer has contacted Cobalt Strike and their parent company Help Systems to confirm the source code’s authenticity but has not heard back.
Thanks to vx-underground for the tip!