alert tls $EXTERNAL_NET any -> $HOME_NET any (msg:"ET MALWARE ABUSE.CH SSL Blacklist Malicious SSL certificate detected (Yakes CnC)"; flow:established,to_client; tls.cert_serial; content:"00:BD:4B:4B:98:C9:8B:2F:20"; fast_pattern; tls.certs; content:"|2a 86 48 86 f7 0d 01 09 01|"; tls.cert_subject; content:"CN=webmaster@localhost"; reference:md5,6cdd93dcb1c54a4e2b036d2e13b51216; reference:url,sslbl.abuse.ch; classtype:domain-c2; sid:2021155; rev:3; metadata:attack_target Client_and_Server, created_at 2015_05_28, deployment Perimeter, performance_impact Low, confidence High, signature_severity Major, tag SSL_Malicious_Cert, updated_at 2024_04_11, mitre_tactic_id TA0011, mitre_tactic_name Command_And_Control, mitre_technique_id T1071, mitre_technique_name Application_Layer_Protocol;)