alert tcp $EXTERNAL_NET any -> $HOME_NET any (msg:"MALWARE [PTsecurity] Babylon RAT pkt checker #1"; flow:established, to_client; dsize:8; content:"|FF|"; offset:1; depth:1; stream_size:server, >,8; stream_size:server, <,130; stream_size:client, >,160; stream_size:client, <,300; flowbits:noalert; flowbits:isset, FB322496_0; flowbits:set, FB322496_1; flowbits:unset, FB322496_0; threshold:type limit, track by_src, count 1, seconds 30; classtype:trojan-activity; metadata:created_at 2017_8_15; reference:url, github.com/ptresearch/AttackDetection; sid:11001784; rev:1;)