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CWE-827: Improper Control of Document Type Definition

 
Improper Control of Document Type Definition
Weakness ID: 827 (Weakness Base)Status: Incomplete
+ Description

Description Summary

The software does not restrict a reference to a Document Type Definition (DTD) to the intended control sphere. This might allow attackers to reference arbitrary DTDs, possibly causing the software to expose files, consume excessive system resources, or execute arbitrary http requests on behalf of the attacker.

Extended Description

As DTDs are processed, they might try to read or include files on the machine performing the parsing. If an attacker is able to control the DTD, then the attacker might be able to specify sensitive resources or requests or provide malicious content.

For example, the SOAP specification prohibits SOAP messages from containing DTDs.

+ Applicable Platforms

Languages

XML

Architectural Paradigms

Web-based

+ Common Consequences
ScopeEffect
Confidentiality

Technical Impact: Read files or directories

If the attacker is able to include a crafted DTD and a default entity resolver is enabled, the attacker may be able to access arbitrary files on the system.

Availability

Technical Impact: DoS: resource consumption (CPU); DoS: resource consumption (memory)

The DTD may cause the parser to consume excessive CPU cycles or memory using techniques such as nested or recursive entity references (CWE-776).

Integrity
Confidentiality
Availability
Access Control

Technical Impact: Execute unauthorized code or commands; Gain privileges / assume identity

The DTD may include arbitrary HTTP requests that the server may execute. This could lead to other attacks leveraging the server's trust relationship with other entities.

+ Observed Examples
ReferenceDescription
Product does not properly reject DTDs in SOAP messages, which allows remote attackers to read arbitrary files, send HTTP requests to intranet servers, or cause a denial of service.
+ Relationships
NatureTypeIDNameView(s) this relationship pertains toView(s)
ChildOfCategoryCategory442Web Problems
Development Concepts (primary)699
ChildOfWeakness ClassWeakness Class706Use of Incorrectly-Resolved Name or Reference
Research Concepts (primary)1000
ChildOfWeakness ClassWeakness Class829Inclusion of Functionality from Untrusted Control Sphere
Research Concepts1000
CanPrecedeWeakness VariantWeakness Variant776Improper Restriction of Recursive Entity References in DTDs ('XML Entity Expansion')
Research Concepts1000
+ References
Daniel Kulp. "Apache CXF Security Advisory (CVE-2010-2076)". 2010-06-16. <http://svn.apache.org/repos/asf/cxf/trunk/security/CVE-2010-2076.pdf>.
+ Content History
Submissions
Submission DateSubmitterOrganizationSource
2010-10-25MITREInternal CWE Team
Modifications
Modification DateModifierOrganizationSource
2011-03-29CWE Content TeamMITREInternal
updated Relationships
2011-06-01CWE Content TeamMITREInternal
updated Common_Consequences
2013-02-21CWE Content TeamMITREInternal
updated Applicable_Platforms
Page Last Updated: July 30, 2014