alert tls $EXTERNAL_NET any -> $HOME_NET any (msg:"ET MALWARE Observed Malicious SSL Cert (MalDoc 2020-03-09)"; flow:established,to_client; tls.cert_subject; content:"CN=WW/O=YY"; bsize:10; fast_pattern; tls.cert_issuer; content:"C=AU, ST=Some-State, L=City, O=Some Company"; bsize:43; reference:md5,bc22e03d068ee58a0b7668fced505b7b; reference:url,twitter.com/JAMESWT_MHT/status/1237028470565240832; classtype:domain-c2; sid:2029596; rev:1; metadata:attack_target Client_and_Server, created_at 2020_03_09, deployment Perimeter, malware_family Maldoc, performance_impact Low, confidence High, signature_severity Major, tag SSL_Malicious_Cert, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2020_03_09, mitre_tactic_id TA0011, mitre_tactic_name Command_And_Control, mitre_technique_id T1071, mitre_technique_name Application_Layer_Protocol;)