Web server process spawning shell commands post webshell upload

Arnold Chan@slaz

•updated Sep 4, 2026•0•0•2

This rule detects suspicious process execution originating from web server applications (e.g., php-fpm, apache2, nginx). It looks for common shell interpreters or command-line utilities (e.g., bash, curl, python) triggered by these web server processes when they contain command execution function strings in their command lines (e.g., system, shell_exec, passthru), which is a common indicator of web shell activity or post-exploitation command execution.