alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET USER_AGENTS User-Agent (single dash)"; flow:to_server,established; http.user_agent; content:"-"; depth:1; endswith; classtype:trojan-activity; sid:2007880; rev:10; metadata:created_at 2010_07_30, confidence High, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2020_09_17;)