alert tls $EXTERNAL_NET any -> $HOME_NET any (msg:"ET MALWARE Observed Malicious SSL Cert (Cobalt Strike CnC)"; flow:established,to_client; tls.cert_subject; content:"C=TR, ST=Istanbul, L=Istanbul Buyuksehir Belediyesi, O=EsT Country, OU=ESTTKEY, CN=alahuakber"; bsize:93; fast_pattern; reference:url,twitter.com/bryceabdo/status/1308778721797640195; classtype:domain-c2; sid:2030903; rev:1; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_and_Server, created_at 2020_09_23, deployment Perimeter, malware_family Cobalt_Strike, performance_impact Low, confidence High, signature_severity Major, tag SSL_Malicious_Cert, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2020_09_23, mitre_tactic_id TA0011, mitre_tactic_name Command_And_Control, mitre_technique_id T1071, mitre_technique_name Application_Layer_Protocol;)