alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE SSV Agent CnC Activity"; flow:established,to_server; http.request_body; content:"|00 00 00 01 00 00 00 01 00 00 00|"; offset:1; depth:11; fast_pattern; pcre:"/^[A-F0-9]{32}/R"; reference:url,github.com/ptresearch/AttackDetection/tree/master/APT31; reference:md5,db1673a1e8316287cb940725bb6caa68; classtype:command-and-control; sid:2033650; rev:2; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, created_at 2021_08_03, deployment Perimeter, deployment SSLDecrypt, performance_impact Low, confidence High, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2021_08_03;)