077. Detecting Windows Sandbox Abuse

Hello everyone! We often use sandboxes for malware triage, but what about adversaries? Can they abuse sandboxes to execute malicious code? And the answer is - yes!

ESET presented a report on MirrorFace attack against a Central European diplomatic institute. Among other malware, the threat actors used a heavily customised variant of AsyncRAT. And they run it... inside Windows Sandbox!

The adversary created a scheduled task to run Windows Sandbox with a WSB file as argument. So, we can hunt for such activity using the following query:

event_type: "processcreatewin"

AND

proc_file_name: ("WindowsSandbox.exe" OR "wsb.exe")

AND

cmdline: "wsb"

Make sure you checked the report - it's full of interesting detection opportunities!

See you tomorrow!

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