Tag Archives: CWE- 827

CWE-827 – Improper Control of Document Type Definition

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Description

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.

Modes of Introduction:

– Implementation

Likelihood of Exploit:

 

Related Weaknesses

CWE-706
CWE-829
CWE-776

 

Consequences

Confidentiality: 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: 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: Execute Unauthorized Code or Commands, Gain Privileges or 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.

 

Potential Mitigations

CVE References

 

  • CVE-2010-2076
    • 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.