PowerShell Base64 Encoded IEX Cmdlet Execution
This rule detects the execution of PowerShell commands that utilize base64 encoded 'IEX' (Invoke-Expression) cmdlets. Adversaries often encode malicious PowerShell scripts in base64 to evade detection and obfuscate their intentions. The rule specifically looks for patterns indicative of base64 encoded 'IEX' calls, including variations with 'New-Object' and different casing, as well as UTF-16 LE encoded versions of common 'IEX' patterns.
Sigma
