alert tcp $EXTERNAL_NET any -> $HOME_NET any (msg:"MALWARE [PTsecurity] Cybergate/Rebhip/Spyrat Backdoor"; flow:established, to_client; dsize:69<>80; content:"|0d0a|"; fast_pattern; stream_size:server, >,0; stream_size:client, >,0; stream_size:server, <,200; stream_size:client, <,200; flowbits:isset, FB117960_3; flowbits:unset, FB117960_3; threshold:type limit, track by_src, count 1, seconds 30; classtype:trojan-activity; metadata:created_at 2017_7_13; reference:url, github.com/ptresearch/AttackDetection; sid:11001531; rev:2;)