alert tls $EXTERNAL_NET any -> $HOME_NET any (msg:"ET MALWARE Observed Malicious FIN12 Related SSL Cert"; flow:established,to_client; tls.cert_subject; content:"OU=Delegated Licensor,KYP SDT LTD"; fast_pattern; pcre:"/CN=(?:[^\r\n]+?\.)?OU=Delegated\ Licensor,KYP\ SDT\ LTD(?!\.)/"; reference:url,www.mandiant.com/resources/fin12-ransomware-intrusion-actor-pursuing-healthcare-targets; classtype:trojan-activity; sid:2034177; rev:1; metadata:attack_target Client_Endpoint, created_at 2021_10_12, deployment Perimeter, malware_family Fin12, confidence High, signature_severity Major, tag SSL_Malicious_Cert, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2021_10_12;)