alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET POLICY OS X Software Update Request Outbound"; flow:established,to_server; http.user_agent; content:"Software Update|2F|"; startswith; content:"|20|Darwin|2F|"; within:48; reference:url,www.apple.com/softwareupdate/; classtype:policy-violation; sid:2013503; rev:4; metadata:created_at 2011_08_31, confidence High, signature_severity Informational, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2020_04_20;)