alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET POLICY exe download without User Agent"; flow:established,to_server; http.method; content:"GET"; http.uri; content:".exe"; endswith; nocase; http.header_names; content:!"|0d 0a|User-Agent|0d 0a|"; http.host; content:!"download.windowsupdate.com"; classtype:policy-violation; sid:2003179; rev:11; metadata:created_at 2010_07_30, confidence High, signature_severity Informational, updated_at 2024_02_06;)