alert http $EXTERNAL_NET any -> $HTTP_SERVERS any (msg:"GPL WEB_SERVER robot.txt access"; flow:to_server,established; content:"/robot.txt"; http_uri; nocase; reference:nessus,10302; classtype:web-application-activity; sid:2101857; rev:5; metadata:created_at 2010_09_23, signature_severity Unknown, updated_at 2019_07_26;)