alert tcp $HOME_NET any -> $EXTERNAL_NET any (msg:"MALWARE [PTsecurity] Cybergate/Rebhip/Spyrat pkt checker #3"; flow:established, to_server; dsize:1; content:"|0a|"; fast_pattern; depth:1; stream_size:server, >,0; stream_size:client, >,0; stream_size:server, <,5; stream_size:client, <,47; flowbits:isset, FB117960_2; flowbits:unset, FB117960_2; flowbits:set, FB117960_3; flowbits:noalert; classtype:trojan-activity; metadata:created_at 2017_7_13; reference:url, github.com/ptresearch/AttackDetection; sid:11001530; rev:2;)