alert tcp $HOME_NET any -> $EXTERNAL_NET [53, 443] (msg:"PROXY [PTsecurity] Bunitu Successful Connection"; flow:established, to_server; dsize:37; content:"|00|"; offset:1; depth:1; stream_size:server, >,0; stream_size:server, <,52; stream_size:client, >,0; stream_size:client, <,53; flowbits:isset, FB70820_1; reference:url, rules.ptsecurity.com; classtype:trojan-activity; sid:11000342; rev:11;)