alert tls $EXTERNAL_NET any -> $HOME_NET any (msg:"ET MALWARE ABUSE.CH SSL Blacklist Malicious SSL Certificate Detected (Sinkhole)"; flow:established,to_client; tls.cert_serial; content:"00:99:60:FE:ED:86:B8:81:83"; tls.cert_subject; content:"O=Sinkhole.Ru"; fast_pattern; content:"CN=*"; reference:url,sslbl.abuse.ch; classtype:domain-c2; sid:2022907; rev:4; metadata:attack_target Client_and_Server, created_at 2016_06_21, deployment Perimeter, deprecation_reason Age, performance_impact Low, confidence High, signature_severity Major, tag SSL_Malicious_Cert, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2024_04_08, reviewed_at 2024_04_08, mitre_tactic_id TA0042, mitre_tactic_name Resource_Development, mitre_technique_id T1587, mitre_technique_name Develop_Capabilities;)