Velvet Ant Operation Highland: Nginx FastCGI SSH Bridge Detection

Ibrahim Saud@tektrix

•updated Jun 30, 2026•0•0•6

Detects anomalous activity consistent with the Velvet Ant 'Operation Highland' methodology, which leverages Nginx/FastCGI to bridge external requests to internal SSH execution. The rule monitors three conditions: 1) HTTP POST requests to internal endpoints containing SSH-related command parameters; 2) suspicious Nginx configuration modifications or reload events; and 3) spawning of SSH processes by FastCGI handlers. Findings are correlated by time and entity to identify potential persistence or lateral movement mechanisms.