alert tls $EXTERNAL_NET any -> $HOME_NET any (msg:"ET MALWARE Observed Malicious SSL Cert (BitRAT CnC)"; flow:established,to_client; tls.cert_subject; content:"CN=Silver"; bsize:9; fast_pattern; tls.cert_issuer; content:"CN=Silver"; bsize:9; reference:md5,949f4223f86d23ec243d1e23dd0a28c9; reference:url,twitter.com/reecdeep/status/1345411411829260289; classtype:domain-c2; sid:2031545; rev:1; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_and_Server, created_at 2021_01_25, deployment Perimeter, malware_family BitRAT, performance_impact Low, confidence High, signature_severity Major, tag SSL_Malicious_Cert, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2021_01_25, mitre_tactic_id TA0011, mitre_tactic_name Command_And_Control, mitre_technique_id T1071, mitre_technique_name Application_Layer_Protocol;)