alert tcp $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE Netwire RAT Check-in (set)"; flow:established,to_server; flowbits:set,ET.NetwireRAT.Client; flowbits:noalert; stream_size:server,<,5; dsize:69; content:"|41 00 00 00 03|"; depth:5; reference:url,www.circl.lu/pub/tr-23/; reference:url,unit42.paloaltonetworks.com/new-release-decrypting-netwire-c2-traffic/; classtype:trojan-activity; sid:2018426; rev:4; metadata:attack_target Client_Endpoint, created_at 2014_04_28, deployment Perimeter, signature_severity Major, updated_at 2024_03_14, reviewed_at 2024_03_06;)