AMSI Bypass via amsiContext Patching & RC4 Key in PS ScriptBlock

Ankit Mehta@Secvyn

•updated Sep 7, 2026•5•0•2

Detects evidence of PowerShell AMSI (Antimalware Scan Interface) bypass attempts, including memory patching of amsiContext, usage of known malicious RC4 keys, or reflection-based tampering with AmsiUtils. These techniques are commonly used by attackers to disable AMSI scanning capabilities and execute malicious scripts undetected.