alert tls $EXTERNAL_NET any -> $HOME_NET any (msg:"ET MALWARE ABUSE.CH SSL Blacklist Malicious SSL certificate detected (Gootkit CnC)"; flow:established,from_server; content:"|55 04 03|"; content:"|10|www."; distance:1; within:5; content:".com"; distance:8; within:4; content:"|55 04 0a|"; distance:0; pcre:"/^.{2}[a-zA-Z0-9]+\x2e[01]/R"; content:"|55 04 06|"; distance:0; content:"|02|US"; distance:1; within:3; reference:url,sslbl.abuse.ch; classtype:domain-c2; sid:2022480; rev:5; metadata:attack_target Client_and_Server, created_at 2016_02_01, deployment Perimeter, performance_impact Low, confidence High, signature_severity Major, tag SSL_Malicious_Cert, updated_at 2024_07_04, mitre_tactic_id TA0011, mitre_tactic_name Command_And_Control, mitre_technique_id T1071, mitre_technique_name Application_Layer_Protocol;)