alert tcp-pkt $HOME_NET any -> $EXTERNAL_NET 1024: (msg:"ET MALWARE Win32/Nitol.A CnC Checkin M3"; flow:to_server,established; dsize:8; content:"|04 00 00 00 1b 8d 34 01|"; threshold:type both, track by_src, count 10, seconds 120; stream_size:server, =, 1; reference:url,asec.ahnlab.com/en/44504; reference:md5,f01b49498b82320973c6006ee117f91e; classtype:trojan-activity; sid:2043277; rev:1; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, created_at 2023_01_11, deployment Perimeter, malware_family Win32_Nitol_A, confidence High, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2023_01_11, reviewed_at 2025_10_24;)