alert tls $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE Observed Sainbox Domain in TLS SNI"; flow:established,to_server; tls.sni; bsize:22; content:"yrmajnbxpt.localto.net"; fast_pattern; classtype:command-and-control; sid:2069281; rev:1; metadata:attack_target Client_Endpoint, created_at 2026_05_14, deployment Perimeter, malware_family Sainbox, confidence High, signature_severity Major, tag SSL_Malicious_Cert, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2026_05_14;)