Fileless Powershell Dropper, (Mon, Oct 17th)

I found an interesting Powershell script that drops a malware on the victim’s computer. The dropped malware is not new (It’s kinda old, though) but the dropper has a very low Virustotal score. The script was detected by one of my hunting rules on VT. It is called “autopowershell.ps1” and has only a score of 3/61 (SHA256:3750576978bfd204c5ac42ee70fb5c21841899878bacc37151370d23e750f8c4)[1]. By “fileless”, it means that the malware tries to reduce at the minimum interactions with the file system. But, to achieve persistence, it must write something on the disk. Most of the time, it’s done through registry keys. That’s what happens with this sample:

Article Link: InfoSec Handlers Diary Blog - SANS Internet Storm Center