alert tcp $EXTERNAL_NET !$HTTP_PORTS -> $HOME_NET any (msg:"MALWARE [PTsecurity] Tofsee.bot pkt57 connection"; flow:established, to_client; dsize:57; flags:PA; stream_size:client,<,200; stream_size:server,=,258; flowbits:isset, PT.Tofsee_0; flowbits:noalert; flowbits:unset, PT.Tofsee_0; flowbits:set, PT.Tofsee_1; classtype:trojan-activity; metadata:created_at 2017_6_2; reference:url, github.com/ptresearch/AttackDetection; sid:11001388; rev:2;)