alert tls any any -> any any (msg:"REMOTE [PTsecurity] SilentTrinity FB set ST_checker3"; flow:established, to_client; stream_size:client, <,3500; stream_size:server, <,8000; content:"|17030303|"; depth:4; byte_test:1,>=,0x03,0,relative; byte_test:1,<=,0x04,0,relative; flowbits:noalert; flowbits:isset, ST_checker2; flowbits:unset, ST_checker2; flowbits:set, ST_checker3; reference:url, rules.ptsecurity.com; classtype:trojan-activity; sid:11004399; rev:9;)