alert tls $EXTERNAL_NET any -> $HOME_NET any (msg:"ET MALWARE Observed Malicious SSL Cert (MirrorThief CnC)"; flow:from_server,established; tls.cert_subject; content:"CN=magento-analytics.com"; nocase; endswith; fast_pattern; tls.cert_issuer; content:"C=US, O=Let's Encrypt, CN=Let's Encrypt Authority X3"; reference:url,blog.netlab.360.com/ongoing-credit-card-data-leak/; classtype:domain-c2; sid:2027342; rev:5; metadata:attack_target Client_and_Server, created_at 2019_05_09, deployment Perimeter, performance_impact Low, confidence High, signature_severity Major, tag SSL_Malicious_Cert, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2020_09_17, mitre_tactic_id TA0042, mitre_tactic_name Resource_Development, mitre_technique_id T1587, mitre_technique_name Develop_Capabilities;)