alert tls $EXTERNAL_NET any -> $HOME_NET any (msg:"MALWARE [PTsecurity] Win32/Spy.Ursnif SSL TOR activity pkt checker #3"; flow:established, to_client; content:"|1703 01 0020|"; depth:5; fast_pattern; content:"|1703|"; distance:32; within:2; stream_size:server, >,3630; stream_size:server, <,3863; stream_size:client, >,1264; stream_size:client, <,2558; flowbits:noalert; flowbits:isset, FB447357_2; flowbits:unset, FB447357_2; flowbits:set, FB447357_3; classtype:trojan-activity; metadata:created_at 2018_1_17; reference:url, github.com/ptresearch/AttackDetection; sid:11002433; rev:1;)