alert tcp $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE Netwire RAT Check-in (set)"; flow:established,to_server; stream_size:server,<,5; dsize:69; content:"|41 00 00 00 99|"; depth:5; flowbits:set,ET.NetwireRAT.Client; flowbits:noalert; reference:url,www.circl.lu/pub/tr-23/; reference:md5,3c4a93154378e17e71830ff164bb54c4; reference:url,unit42.paloaltonetworks.com/new-release-decrypting-netwire-c2-traffic/; classtype:trojan-activity; sid:2029477; rev:3; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, created_at 2019_07_16, deployment Perimeter, confidence High, signature_severity Major, tag Netwire, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2022_08_09;)