alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET HUNTING TA829 CnC Check-in With Unknown Identifier String"; flow:established,to_server; http.method; content:"POST"; http.request_body; content:"|ff ff 00 00 00 00 00 00 00 00 00 00 00 00 00 00|"; startswith; fast_pattern; pcre:"/^(?:(?:[A-Fa-f0-9]{2}\-){5}[A-Fa-f0-9]{2}|[A-Fa-f0-9]{16}|[A-Fa-f0-9]{63,65})\x40/R"; content:"|40|exist"; content:!"|40|RDPE1|40|"; content:!"|40|RUSTY|40|"; content:!"|40|VIVAT|40|"; content:!"|40|GAGA1|40|"; content:!"|40|CMPN1|40|"; classtype:command-and-control; sid:2063197; rev:1; metadata:attack_target Client_Endpoint, created_at 2025_05_29, deployment Perimeter, confidence High, signature_severity Major, tag TA829, updated_at 2025_06_27, former_sid 2862005; target:dest_ip;)