IIS w3wp.exe Spawning cmd/PowerShell or Writing ASPX Web Shells

Ibrahim Saud@tektrix

•updated Jun 27, 2026•0•0•4

This rule detects potential web shell activity on Windows IIS servers by monitoring for suspicious process creation and file write events originating from the w3wp.exe worker process. Specifically, it flags when w3wp.exe spawns command shells (cmd, powershell), database management utilities (sqlcmd, osql), or network discovery/transfer tools (curl, wget, certutil, bitsadmin). It also detects the creation or modification of common web shell file extensions (.aspx, .ashx, .asmx) within web root directories.