Sliver is an open-source penetration testing tool developed in the Go programming language. Cobalt Strike and Metasploit are major examples of penetration testing tools used by many threat actors, and various attack cases involving these tools have been covered here on the ASEC blog. Recently, there have been cases of threat actors using Sliver in addition to Cobalt Strike and Metasploit.

The ASEC (AhnLab Security Emergency response Center) analysis team is monitoring attacks against systems with either unpatched vulnerabilities or misconfigured settings. During this process, we have recently discovered a Sliver backdoor being installed through what is presumed to be vulnerability exploitation on certain software. Not only did threat actors use the Sliver backdoor, but they also used the BYOVD (Bring Your Own Vulnerable Driver) malware to incapacitate security products and install reverse shells.