alert tcp $HOME_NET any -> $EXTERNAL_NET any (msg:"ET RETIRED Win32/Unknown RAT CnC Checkin"; flow:established,to_server; stream_size:client,>,600; content:"|29 01 00 00|"; startswith; fast_pattern; byte_jump:4,0,relative,little,from_beginning,post_offset -1; isdataat:!2,relative; reference:md5,324877533d7f0c4014e0f046d0c28d39; reference:md5,dd43c6237024d7867e5e441871c64402; classtype:trojan-activity; sid:2049152; rev:3; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, affected_product Windows_11, attack_target Client_and_Server, created_at 2023_11_10, deployment Perimeter, former_category MALWARE, performance_impact Low, confidence High, signature_severity Major, updated_at 2025_04_17, reviewed_at 2025_04_17; target:src_ip;)