alert tcp $HOME_NET any -> $EXTERNAL_NET $HTTP_PORTS (msg:"ET POLICY External Windows Update in Progress"; flow:established,to_server; http.user_agent; content:"Windows-Update-Agent"; fast_pattern; http.header_names; content:"|0d 0a|Host|0d 0a|"; threshold:type limit, count 1, seconds 300, track by_src; reference:url,windowsupdate.microsoft.com; classtype:policy-violation; sid:2002948; rev:12; metadata:created_at 2010_07_30, confidence High, signature_severity Informational, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2024_03_04;)