alert tls $EXTERNAL_NET any -> $HOME_NET any (msg:"ET MALWARE NamelessC2 SSL/TLS Certificate Observed"; flow:established,to_client; tls.cert_serial; content:"C1:84:FB:D8:3E:A1:86:E2"; fast_pattern; reference:url,github.com/trickster0/NamelessC2/tree/d075534d4be70fed2e0d3f85c8e90ccc7ac5bc85/NamelessServer; classtype:domain-c2; sid:2056363; rev:1; metadata:attack_target Client_Endpoint, tls_state TLSEncrypt, created_at 2024_09_30, deployment Perimeter, malware_family NamelessC2, confidence High, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2024_09_30;)