alert tcp $HOME_NET any -> $EXTERNAL_NET !$HTTP_PORTS (msg:"MALWARE [PTsecurity] Bayrob"; flow:established, to_server; dsize:19; stream_size:server, <,21; stream_size:client, <,52; flowbits:isset, FB145313_3; flowbits:unset, FB145313_3; threshold:type limit, track by_src, count 1, seconds 30; classtype:trojan-activity; metadata:created_at 2017_7_12; reference:url, github.com/ptresearch/AttackDetection; sid:11001521; rev:1;)