alert tls $EXTERNAL_NET any -> $HOME_NET any (msg:"ET MALWARE ABUSE.CH SSL Blacklist Malicious SSL Certificate Detected (Shifu)"; flow:established,to_client; tls.cert_serial; content:"00:A3:C1:AE:7C:85:E8:A5:6B"; fast_pattern; tls.cert_subject; content:"O=Internet|20|Widgits|20|Pty|20|Ltd"; reference:md5,5666cb1caca3fde7dd1c8195b76eac8e; reference:url,sslbl.abuse.ch; classtype:domain-c2; sid:2022058; rev:5; metadata:attack_target Client_and_Server, created_at 2015_11_10, deployment Perimeter, performance_impact Low, confidence High, signature_severity Major, tag SSL_Malicious_Cert, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2024_04_08, mitre_tactic_id TA0011, mitre_tactic_name Command_And_Control, mitre_technique_id T1071, mitre_technique_name Application_Layer_Protocol;)