alert tls $EXTERNAL_NET 443 -> $HOME_NET any (msg:"ET MALWARE Malicious SSL certificate detected (Possible Sinkhole)"; flow:established,from_server; content:"|16|"; content:"|0b|"; within:8; content:"|55 04 0a|"; distance:0; content:"|0a|infosec.jp"; distance:1; within:11; content:"|55 04 03|"; distance:0; content:"|0e|www.infosec.jp"; distance:1; within:15; content:"snowyowl@jpnsec.com"; distance:0; reference:md5,ef5fa2378307338d4e75dece88158d77; classtype:domain-c2; sid:2022324; rev:5; metadata:attack_target Client_and_Server, created_at 2016_01_01, deployment Perimeter, performance_impact Low, confidence Medium, signature_severity Major, tag SSL_Malicious_Cert, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2024_07_04, mitre_tactic_id TA0011, mitre_tactic_name Command_And_Control, mitre_technique_id T1071, mitre_technique_name Application_Layer_Protocol;)