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Common Weakness Enumeration

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ID

CWE-12: ASP.NET Misconfiguration: Missing Custom Error Page

Weakness ID: 12
Abstraction: Variant
Structure: Simple
Status: Draft
Presentation Filter:
+ Description
An ASP .NET application must enable custom error pages in order to prevent attackers from mining information from the framework's built-in responses.
+ Relationships

The table(s) below shows the weaknesses and high level categories that are related to this weakness. These relationships are defined as ChildOf, ParentOf, MemberOf and give insight to similar items that may exist at higher and lower levels of abstraction. In addition, relationships such as PeerOf and CanAlsoBe are defined to show similar weaknesses that the user may want to explore.

+ Relevant to the view "Research Concepts" (CWE-1000)
NatureTypeIDName
ChildOfClassClass - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More general than a Base weakness.756Missing Custom Error Page
+ Relevant to the view "Development Concepts" (CWE-699)
NatureTypeIDName
MemberOfCategoryCategory - a CWE entry that contains a set of other entries that share a common characteristic.519.NET Environment Issues
+ Background Details
The mode attribute of the <customErrors> tag defines whether custom or default error pages are used.
+ Modes Of Introduction

The different Modes of Introduction provide information about how and when this weakness may be introduced. The Phase identifies a point in the software life cycle at which introduction may occur, while the Note provides a typical scenario related to introduction during the given phase.

PhaseNote
Implementation
Operation
+ Applicable Platforms
The listings below show possible areas for which the given weakness could appear. These may be for specific named Languages, Operating Systems, Architectures, Paradigms, Technologies, or a class of such platforms. The platform is listed along with how frequently the given weakness appears for that instance.

Languages

ASP.NET (Undetermined Prevalence)

+ Common Consequences

The table below specifies different individual consequences associated with the weakness. The Scope identifies the application security area that is violated, while the Impact describes the negative technical impact that arises if an adversary succeeds in exploiting this weakness. The Likelihood provides information about how likely the specific consequence is expected to be seen relative to the other consequences in the list. For example, there may be high likelihood that a weakness will be exploited to achieve a certain impact, but a low likelihood that it will be exploited to achieve a different impact.

ScopeImpactLikelihood
Confidentiality

Technical Impact: Read Application Data

Default error pages gives detailed information about the error that occurred, and should not be used in production environments. Attackers can leverage the additional information provided by a default error page to mount attacks targeted on the framework, database, or other resources used by the application.
+ Demonstrative Examples

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" />
+ Potential Mitigations

Phase: System Configuration

Handle exceptions appropriately in source code. ASP .NET applications should be configured to use custom error pages instead of the framework default page.

Phase: Architecture and Design

Do not attempt to process an error or attempt to mask it.

Phase: Implementation

Verify return values are correct and do not supply sensitive information about the system.
+ Memberships
This MemberOf Relationships table shows additional CWE Categories and Views that reference this weakness as a member. This information is often useful in understanding where a weakness fits within the context of external information sources.
NatureTypeIDName
MemberOfCategoryCategory - a CWE entry that contains a set of other entries that share a common characteristic.27PK - Environment
MemberOfCategoryCategory - a CWE entry that contains a set of other entries that share a common characteristic.963SFP Secondary Cluster: Exposed Data
+ Taxonomy Mappings
Mapped Taxonomy NameNode IDFitMapped Node Name
7 Pernicious KingdomsASP.NET Misconfiguration: Missing Custom Error Handling
+ References
[REF-65] M. Howard, D. LeBlanc and J. Viega. "19 Deadly Sins of Software Security". McGraw-Hill/Osborne. 2005-07-26.
[REF-66] OWASP, Fortify Software. "ASP.NET Misconfiguration: Missing Custom Error Handling". <http://www.owasp.org/index.php/ASP.NET_Misconfiguration:_Missing_Custom_Error_Handling>.
+ Content History
Submissions
Submission DateSubmitterOrganization
7 Pernicious Kingdoms
Modifications
Modification DateModifierOrganization
2008-07-01Eric DalciCigital
updated References, Demonstrative_Example, Potential_Mitigations, Time_of_Introduction
2008-09-08CWE Content TeamMITRE
updated Relationships, Other_Notes, References, Taxonomy_Mappings
2008-10-14CWE Content TeamMITRE
updated Relationships
2008-11-24CWE Content TeamMITRE
updated Common_Consequences, Other_Notes, Potential_Mitigations
2009-03-10CWE Content TeamMITRE
updated Name, Relationships
2009-07-27CWE Content TeamMITRE
updated Background_Details, Common_Consequences, Other_Notes
2011-06-01CWE Content TeamMITRE
updated Common_Consequences
2011-06-27CWE Content TeamMITRE
updated Common_Consequences
2012-05-11CWE Content TeamMITRE
updated Demonstrative_Examples, Relationships
2012-10-30CWE Content TeamMITRE
updated Potential_Mitigations
2013-02-21CWE Content TeamMITRE
updated Potential_Mitigations
2014-07-30CWE Content TeamMITRE
updated Relationships
2017-11-08CWE Content TeamMITRE
updated Demonstrative_Examples, Potential_Mitigations, References, Relationships
Previous Entry Names
Change DatePrevious Entry Name
2009-03-10ASP.NET Misconfiguration: Missing Custom Error Handling

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Page Last Updated: March 29, 2018