C2 Traffic Obfuscated in HTTP Request Body

Darshan Thummar@Mighty

•updated Jun 12, 2026•0•0•7

This rule detects HTTP POST requests where the client body contains a large string (over 200 characters) that appears to be Base64 encoded. The `pcre` (Perl Compatible Regular Expression) `/^[A-Za-z0-9+\/]{200,}={0,2}$/` specifically looks for strings composed of Base64 characters (alphanumeric, '+', '/', and optional '==') with a minimum length of 200 characters. This pattern is often used by malware for command and control (C2) communication to obfuscate data within HTTP traffic.