alert tcp $EXTERNAL_NET !$HTTP_PORTS -> $HOME_NET any (msg:"ET MALWARE [PTsecurity] Ursnif Socks5 Proxy Connection"; flow:established,from_server; flowbits:isset,PT.UrsnifProxy; stream_size:server,=,5; dsize:3; content:"|050100|"; fast_pattern; depth:3; classtype:trojan-activity; sid:2025445; rev:2; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, created_at 2018_03_28, deployment Perimeter, malware_family ursnif, performance_impact Low, confidence High, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2019_07_26;)