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Resolving IIS hosted pages loading blank when requested filtering in IIS is enabled

Summary​

Use the following PowerShell command to set the Request Filtering behavior in IIS so unlisted file extensions are denied:

Set-WebConfigurationProperty -pspath 'MACHINE/WEBROOT/APPHOST'  -filter "system.webServer/security/requestFiltering/fileExtensions" -name "allowUnlisted" -value "False" -errorAction SilentlyContinue

Issue​

In IIS there is an installable component called Request Filtering. An element within that functionality allows you to allow or deny certain file extensions from loading in the webpage.

allowUnlisted - Specifies whether the Web server should process files that have unlisted file name extensions. If you set this attribute to true, you must list all file name extensions you want to deny. If you set this attribute to false, you must list all file name extensions you want to allow. The default value is true.

Command used​

Set-WebConfigurationProperty -pspath 'MACHINE/WEBROOT/APPHOST'  -filter "system.webServer/security/requestFiltering/fileExtensions" -name "allowUnlisted" -value "False" -errorAction SilentlyContinue

Enabling this option is common practice when securing IIS; however, this can potentially break Access Information Center (AIC) and SI Reporting Console reports from loading as these both utilize IIS.

For more context on this functionality see: https://docs.microsoft.com/en-us/iis/configuration/system.webserver/security/requestfiltering/fileextensions/

If this is the case, you can run the following commands in PowerShell as Administrator to add the necessary extensions:

Add-WebConfigurationProperty -pspath 'MACHINE/WEBROOT/APPHOST'  -filter "system.webServer/security/requestFiltering/fileExtensions" -name "." -value @{fileExtension=‘.svc’} -errorAction SilentlyContinue

Add-WebConfigurationProperty -pspath 'MACHINE/WEBROOT/APPHOST'  -filter "system.webServer/security/requestFiltering/fileExtensions" -name "." -value @{fileExtension='.xaml'} -errorAction SilentlyContinue

Add-WebConfigurationProperty -pspath 'MACHINE/WEBROOT/APPHOST'  -filter "system.webServer/security/requestFiltering/fileExtensions" -name "." -value @{fileExtension='.xap'} -errorAction SilentlyContinue

Add-WebConfigurationProperty -pspath 'MACHINE/WEBROOT/APPHOST'  -filter "system.webServer/security/requestFiltering/fileExtensions" -name "." -value @{fileExtension='.xbap'} -errorAction SilentlyContinue

Add-WebConfigurationProperty -pspath 'MACHINE/WEBROOT/APPHOST'  -filter "system.webServer/security/requestFiltering/fileExtensions" -name "." -value @{fileExtension='.ashx'} -errorAction SilentlyContinue

Add-WebConfigurationProperty -pspath 'MACHINE/WEBROOT/APPHOST'  -filter "system.webServer/security/requestFiltering/fileExtensions" -name "." -value @{fileExtension='.js'} -errorAction SilentlyContinue

Add-WebConfigurationProperty -pspath 'MACHINE/WEBROOT/APPHOST'  -filter "system.webServer/security/requestFiltering/fileExtensions" -name "." -value @{fileExtension='.css'} -errorAction SilentlyContinue

Add-WebConfigurationProperty -pspath 'MACHINE/WEBROOT/APPHOST'  -filter "system.webServer/security/requestFiltering/fileExtensions" -name "." -value @{fileExtension='.html'} -errorAction SilentlyContinue

Add-WebConfigurationProperty -pspath 'MACHINE/WEBROOT/APPHOST'  -filter "system.webServer/security/requestFiltering/fileExtensions" -name "." -value @{fileExtension='.'} -errorAction SilentlyContinue

Add-WebConfigurationProperty -pspath 'MACHINE/WEBROOT/APPHOST'  -filter "system.webServer/security/requestFiltering/fileExtensions" -name "." -value @{fileExtension='.aspx'} -errorAction SilentlyContinue

Add-WebConfigurationProperty -pspath 'MACHINE/WEBROOT/APPHOST'  -filter "system.webServer/security/requestFiltering/fileExtensions" -name "." -value @{fileExtension='.png'} -errorAction SilentlyContinue

Add-WebConfigurationProperty -pspath 'MACHINE/WEBROOT/APPHOST'  -filter "system.webServer/security/requestFiltering/fileExtensions" -name "." -value @{fileExtension='.gif'} -errorAction SilentlyContinue

Add-WebConfigurationProperty -pspath 'MACHINE/WEBROOT/APPHOST'  -filter "system.webServer/security/requestFiltering/fileExtensions" -name "." -value @{fileExtension='.woff'} -errorAction SilentlyContinue

Add-WebConfigurationProperty -pspath 'MACHINE/WEBROOT/APPHOST'  -filter "system.webServer/security/requestFiltering/fileExtensions" -name "." -value @{fileExtension='.woff2'} -errorAction SilentlyContinue

Add-WebConfigurationProperty -pspath 'MACHINE/WEBROOT/APPHOST'  -filter "system.webServer/security/requestFiltering/fileExtensions" -name "." -value @{fileExtension='.csv'} -errorAction SilentlyContinue

Add-WebConfigurationProperty -pspath 'MACHINE/WEBROOT/APPHOST'  -filter "system.webServer/security/requestFiltering/fileExtensions" -name "." -value @{fileExtension='.xls'} -errorAction SilentlyContinue

Add-WebConfigurationProperty -pspath 'MACHINE/WEBROOT/APPHOST'  -filter "system.webServer/security/requestFiltering/fileExtensions" -name "." -value @{fileExtension='.xlsx'} -errorAction SilentlyContinue

Submitted by​

  • Ricky Calder

Product​

  • Netwrix Access Analyzer and Netwrix Threat Prevention

Affected Versions​

  • ALL

Affected Module​

  • Netwrix Access Analyzer, AIC, SI Reports

Dev Ticket​

  • N/A

Resolved In Version​

  • N/A

KB Type​

  • How To