alert tls $EXTERNAL_NET any -> $HOME_NET any (msg:"ET MALWARE Observed Malicious SSL Cert (ACBackdoor CnC)"; flow:established,from_server; tls.cert_serial; content:"76:DC:D7:09:68:53:16:74:BB:A8:7B:CC:DE:C4:9D:66:77:43:34:DC"; reference:url,www.intezer.com/blog-acbackdoor-analysis-of-a-new-multiplatform-backdoor/; classtype:domain-c2; sid:2029048; rev:2; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, affected_product Linux, attack_target Client_and_Server, created_at 2019_11_21, deployment Perimeter, malware_family ACBackdoor, performance_impact Low, confidence High, signature_severity Major, tag SSL_Malicious_Cert, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2020_10_22, mitre_tactic_id TA0011, mitre_tactic_name Command_And_Control, mitre_technique_id T1071, mitre_technique_name Application_Layer_Protocol;)