Executive summaryCisco Talos assesses with moderate confidence that a campaign we recently discovered called "BlackWater" is associated with suspected persistent threat actor MuddyWater. Newly associated samples from April 2019 indicate attackers have added three distinct steps to their operations, allowing them to bypass certain security controls and suggesting that MuddyWater's tactics, techniques and procedures (TTPs) have evolved to evade detection. If successful, this campaign would install a PowerShell-based backdoor onto the victim's machine, giving the threat actors remote access. While this activity indicates the threat actor is taking steps to improve its operational security and avoid endpoint detection, the underlying code remains unchanged. The findings outlined in this blog should help threat hunting teams identify MuddyWater's latest TTPs.
In this latest activity, the threat actor first added an obfuscated Visual Basic for Applications (VBA) script to establish persistence as a registry key. Next, the script triggered a PowerShell stager, likely in an attempt to masquerade as a red-teaming tool rather than an advanced actor. The stager would then communicate with one actor-controlled server to obtain a component of the FruityC2 agent script, an open-source framework on GitHub, to further enumerate the host machine. This could allow the threat actor to monitor web logs and determine whether someone uninvolved in the campaign made a request to their server in an attempt to investigate the activity. Once the enumeration commands would run, the agent would communicate with a different C2 and send back the data in the URL field. This ..