snip3-encoded-powershell-structure

id: c85c5b11-a5b9-480d-b9cf-79ba2289f770
name: snip3-encoded-powershell-structure
description: |
  Snip3 is a family of related remote access trojans. Although the malware in this family contain numerous small variations, they all exhibit similar behaviors and techniques.
  The following query looks for the method that Snip3 malware use to obfuscate PowerShell commands with UTF8 encoding. This technique is intended to evade detection from security products, and avoids the more standard switches used for encoding in malware such as Emotet.
  At present, this method of encoding is much more rare, being seen largely with loader installation of RevengeRAT, AsyncRAT and other RATs used in campaigns targeting the aviation industry.
requiredDataConnectors:
- connectorId: MicrosoftThreatProtection
  dataTypes:
  - DeviceFileEvents
tactics:
- Defense evasion
query: |
  DeviceFileEvents
  | where InitiatingProcessFileName =~ "powershell.exe"
  | where InitiatingProcessCommandLine has_all ("IEX","Text.Encoding","UTF8.GetString(@")
  | where InitiatingProcessCommandLine has_any ("Unrestricted","Hidden")