Information
The notListedIsapisAllowed attribute is a server-level setting that is located in the ApplicationHost.config file in the <isapiCgiRestriction> element of the <system.webServer> section under <security>. This element ensures that malicious users cannot copy unauthorized ISAPI binaries to the Web server and then run them.
It is recommended that notListedIsapisAllowed be set to false.
Rationale:
Restricting this attribute to false will help prevent potentially malicious ISAPI extensions from being run.
Impact:
Unauthorized ISAPI binaries will not be allowed.
Solution
To use IIS Manager to set the notListedIsapisAllowed attribute to false:
Open IIS Manager as Administrator
In the Connections pane on the left, select server to be configured
In Features View, select ISAPI and CGI Restrictions; in the Actions pane, select Open Feature
In the Actions pane, select Edit Feature Settings
In the Edit ISAPI and CGI Restrictions Settings dialog, clear the Allow unspecified ISAPI modules check box, if checked
Click OK
Enter the following command in AppCmd.exe to configure:
%systemroot%\system32\inetsrv\appcmd.exe set config -section:system.webServer/security/isapiCgiRestriction /notListedIsapisAllowed:false
OR
Enter the following command in PowerShell to configure:
Set-WebConfigurationProperty -pspath 'MACHINE/WEBROOT/APPHOST' -filter 'system.webServer/security/isapiCgiRestriction' -name 'notListedIsapisAllowed' -value 'False'
Default Value:
The default value for notListedIsapisAllowed is false.