Microsoft ASP.NET ValidateRequest Filters Bypass
Medium Nessus Plugin ID 58601
SynopsisThe web application framework used on the remote host may be susceptible to cross-site scripting attacks.
DescriptionAccording to the HTTP headers received from the remote host, the web server is configured to use the ASP.NET framework.
This framework includes the ValidateRequest feature, which is used by ASP.NET web applications to filter user input in an attempt to prevent cross-site scripting attacks. However, this set of filters can be bypassed if it is the sole mechanism used for protection by a web application.
Since Nessus is unable to remotely gather enough information to determine if the ValidateRequest feature is used in an unsafe manner, this plugin will report all web servers using ASP.NET when the 'Report Paranoia' configuration setting is set to 'Paranoid (more false alarms)'. Determining if an actual security risk exists requires manual verification.
SolutionDetermine if any ASP.NET web applications solely rely on the ValidateRequest feature, and use additional protections if necessary.