251. That's How MostereRAT Abuses Ruby

Hello everyone!

I think everyone is already got used to the fact that adversaries abuse Python. But there're still more interesting examples of Command and Scripting Interpreter (T1059)!

For example, according to this report, MostereRAT leveraged a a Ruby script to execute one of the stages:

C:\ProgramData\Windows\ruby\ruby.exe -e "system('start C:\ProgramData\Windows\svchost.exe C:\ProgramData\Windows\svchost.db channel-8df91be7c24e');exit();"

As you can see, ruby.exe runs from an uncommon path. You can use it and, for example, exclude common paths for your environment, to build your hunting query:

event_type: "processcreatewin"

AND

proc_file_originalfilename: "ruby.exe"

AND

proc_file_path: "programdata"

See you tomorrow!

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