216. An Interesting Case of Rundll32 Abuse

Hello everyone!

Do you remember I mentioned that rundll32.exe is my favourite threat hunting target? Let's look at another example!

We'll look inside the report by eSentire on Interlock. The adversary abused rundll32.exe and Windows Shell Common Dll to run a malcious LNK file:

rundll32 shell32.dll,ShellExec_RunDLL “<8_CHARS>.lnk”

So, based on this, we can form a simple hypothesis: an adversary may use rundll32.exe and Windows Shell Common Dll to run a malcious LNK file:

event_type: "processcreatewin"

AND

proc_file_path: "rundll32.exe"

AND

cmdline: ("shell32.dll" AND *lnk)

There's another interesting rundll32.exe abuse example in the report. Can you find it?

See you tomorrow!

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