alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE W2KM_BARTALEX Downloading Payload 2"; flow:established,to_server; http.method; content:"GET"; http.uri; content:".txt"; pcre:"/\/\d{4,}\.txt$/"; http.user_agent; content:"Mozilla/4.0 (compatible|3b 20|Win32|3b 20|WinHttp.WinHttpRequest.5)"; fast_pattern; http.header_names; content:!"Referer|0d 0a|"; content:"Accept|0d 0a|"; content:"Accept-Language|0d 0a|"; reference:md5,545ee3114faa5abd994f9730713f2261; classtype:trojan-activity; sid:2021304; rev:5; metadata:created_at 2015_06_19, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2020_05_29;)