alert tls $EXTERNAL_NET any -> $HOME_NET any (msg:"ET MALWARE Observed Malicious SSL Cert (NHS UK Covid Passport Phish)"; flow:from_server,established; tls.cert_subject; content:"CN=nhs.applyonline20.com"; nocase; fast_pattern; endswith; classtype:domain-c2; sid:2033286; rev:1; metadata:attack_target Client_and_Server, created_at 2021_07_08, deployment Perimeter, performance_impact Low, confidence High, signature_severity Major, tag SSL_Malicious_Cert, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2021_07_08, mitre_tactic_id TA0042, mitre_tactic_name Resource_Development, mitre_technique_id T1587, mitre_technique_name Develop_Capabilities;)