alert tls $EXTERNAL_NET any -> $HOME_NET any (msg:"ET MALWARE Observed Malicious SSL Cert (MageCart Group 5 Staging Domain)"; flow:from_server,established; tls.cert_subject; content:"CN=localhost.localdomain"; tls.cert_serial; content:"00:FF:A1:F0:8C:C1:45:51:3E"; reference:url,go.flashpoint.com/docs/inside-magecart-by-Flashpoint-and-RiskIQ; classtype:domain-c2; sid:2026603; rev:2; metadata:affected_product Web_Browsers, attack_target Client_and_Server, created_at 2018_11_13, deployment Perimeter, malware_family MageCart, performance_impact Low, confidence High, signature_severity Major, tag SSL_Malicious_Cert, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2020_08_27, mitre_tactic_id TA0011, mitre_tactic_name Command_And_Control, mitre_technique_id T1071, mitre_technique_name Application_Layer_Protocol;)