alert tls $EXTERNAL_NET any -> $HOME_NET any (msg:"ET MALWARE Observed Malicious SSL Cert (Bazar Backdoor)"; flow:established,to_client; tls.cert_subject; content:"C=KZ, ST=Astana, L=Astana, O=NN Fern, OU=KZ System, CN=forenzik.kz"; bsize:66; fast_pattern; reference:url,twitter.com/z0ul_/status/1374121916143919106; reference:md5,4cf6fb8514073319e7759b4f66d13f08; classtype:domain-c2; sid:2032313; rev:1; metadata:attack_target Client_and_Server, created_at 2021_03_23, deployment Perimeter, performance_impact Low, confidence High, signature_severity Major, tag SSL_Malicious_Cert, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2021_03_23, mitre_tactic_id TA0011, mitre_tactic_name Command_And_Control, mitre_technique_id T1071, mitre_technique_name Application_Layer_Protocol;)