alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE WBK Download from dotted-quad Host"; flow:established,to_server; http.uri; content:".wbk"; endswith; nocase; http.host; content:"."; offset:1; depth:3; content:"."; within:4; content:"."; within:4; pcre:"/(?:\d{1,3}\.){3}\d{1,3}$/"; http.request_line; content:".wbk HTTP/1."; fast_pattern; classtype:trojan-activity; sid:2034396; rev:3; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, created_at 2021_11_09, deployment Perimeter, confidence High, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2023_04_10;)