alert tcp-pkt $EXTERNAL_NET any -> $HOME_NET any (msg:"ET RETIRED Win32/Gh0st RAT Variant CnC Checkin response"; flow:established,to_client; stream_size:server,=,28; dsize:27; content:"|1b 00 00 00|"; startswith; pcre:"/^(?:[0-9]\x00){9}/R"; pcre:"/(?:\x01\x00\x01$|\x00{3}$)/"; byte_jump:4,0, little, from_beginning, post_offset -1; isdataat:!2,relative; reference:md5,77bd9926a4b41c14259e20c1f90e22aa; classtype:trojan-activity; sid:2039834; rev:3; metadata:attack_target Client_and_Server, created_at 2022_11_23, deployment Perimeter, former_category MALWARE, malware_family Win32_Gh0st, performance_impact Low, confidence High, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2024_09_23, reviewed_at 2024_09_23;)