alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE MS_D0wnl0ad3r Checkin"; flow:to_server,established; http.method; content:"GET"; http.uri; content:".php?hwid="; http.header; content:"en-gb|5c|Accept"; http.user_agent; content:"Gecko/20070725 Firefox/2.0.0.6"; http.header_names; content:!"Referer"; classtype:command-and-control; sid:2026363; rev:3; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, created_at 2018_09_25, deployment Perimeter, confidence High, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2020_08_25;)