alert http $EXTERNAL_NET any -> $HOME_NET any (msg:"ET SCAN Hydra User-Agent"; flow:established,to_server; http.user_agent; content:"Mozilla/4.0 (Hydra)"; startswith; nocase; fast_pattern; threshold:type limit, track by_src,count 1, seconds 60; reference:url,freeworld.thc.org/thc-hydra; classtype:attempted-recon; sid:2011497; rev:6; metadata:created_at 2010_09_28, confidence High, signature_severity Informational, updated_at 2024_03_08;)