alert http $EXTERNAL_NET any -> $HOME_NET any (msg:"ET MALWARE Manjusaka C2 Heartbeat Response"; flow:established,to_client; http.stat_code; content:"200"; http.content_type; content:"image/png"; http.content_len; content:"5"; bsize:1; http.response_body; content:"|1a 1a 6e 04 29|"; fast_pattern; bsize:5; threshold:type limit, seconds 360, count 1, track by_dst; reference:url,corelight.com/blog/detecting-manjusaka-c2-framework; classtype:command-and-control; sid:2039602; rev:1; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, created_at 2022_10_31, deployment Perimeter, deployment SSLDecrypt, malware_family Manjusaka, confidence High, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2022_10_31, reviewed_at 2025_10_24;)