CWE-12: ASP.NET Misconfiguration: Missing Custom Error Page
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Edit Custom FilterAn ASP .NET application must enable custom error pages in order to prevent attackers from mining information from the framework's built-in responses.
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![]() Languages ASP.NET (Undetermined Prevalence) Example 1 The mode attribute of the <customErrors> tag in the Web.config file defines whether custom or default error pages are used. In the following insecure ASP.NET application setting, custom error message mode is turned off. An ASP.NET error message with detailed stack trace and platform versions will be returned. (bad code)
Example Language: ASP.NET
<customErrors mode="Off" />
A more secure setting is to set the custom error message mode for remote users only. No defaultRedirect error page is specified. The local user on the web server will see a detailed stack trace. For remote users, an ASP.NET error message with the server customError configuration setting and the platform version will be returned. (good code)
Example Language: ASP.NET
<customErrors mode="RemoteOnly" />
Another secure option is to set the mode attribute of the <customErrors> tag to use a custom page as follows: (good code)
Example Language: ASP.NET
<customErrors mode="On" defaultRedirect="YourErrorPage.htm" />
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