236. That's How SHAMOS Bypasses Gatekeeper Checks

Hello everyone!

Let's talk a bit about defense evasion. But not Windows. And not Linux. Today we're going to look at a procedure related to the following technique: Subvert Trust Controls: Gatekeeper Bypass (T1553.001).

And we'll look at SHAMOS, a variant of Atomic macOS Stealer (AMOS). To bypass Gatekeeper checks, it clears all attributes using xattr:

sudo -S xattr -c /tmp/update

We can hunt for clearing attributes for suspicious files located under /tmp:

event_type: "processcreatemac"

AND

proc_file_path: "xattr"

AND

cmdline: ("c" AND "tmp")

See you tomorrow!

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