alert tcp $HOME_NET any -> $EXTERNAL_NET !$HTTP_PORTS (msg:"MALWARE [PTsecurity] Bayrob pkt checker #2"; flow:established, to_server; dsize:2; stream_size:server, =,1; stream_size:client, <,13; flowbits:noalert; flowbits:isset, FB145313_1; flowbits:unset, FB145313_1; flowbits:set, FB145313_2; classtype:trojan-activity; metadata:created_at 2017_7_12; reference:url, github.com/ptresearch/AttackDetection; sid:11001519; rev:1;)