alert tcp $HOME_NET any -> $EXTERNAL_NET any (msg:"ET DELETED MSN User-Agent Activity"; flow:established,to_server; content:"User-Agent|3a| MSMSGS"; http_header; nocase; reference:url,www.hypothetic.org/docs/msn/general/http_examples.php; classtype:policy-violation; sid:2009376; rev:5; metadata:created_at 2010_07_30, signature_severity Unknown, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2019_07_26;)