alert tls $HOME_NET any -> $EXTERNAL_NET any (msg:"MALWARE [PTsecurity] TrickBot.Spy SSL connection"; flow:established, to_server; content:"|1703|"; depth:2; byte_test:2, >=,256, 1, relative; byte_test:2, <=,304, 1, relative; stream_size:server, >,2488; stream_size:server, <,4101; stream_size:client, >,1008; stream_size:client, <,1961; flowbits:isset, FB566923_3; flowbits:unset, FB566923_3; threshold:type limit, track by_src, count 1, seconds 30; classtype:trojan-activity; metadata:created_at 2018_05_11; reference:url, github.com/ptresearch/AttackDetection; sid:11002943; rev:1;)