alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET POLICY libwww-perl User-Agent"; flow:established,to_server; http.user_agent; content:"libwww-perl/"; depth:12; nocase; reference:url,www.useragentstring.com/pages/useragentstring.php; classtype:attempted-recon; sid:2013030; rev:5; metadata:created_at 2011_06_14, confidence High, signature_severity Informational, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2020_08_20;)