Tag Archives: Improper Neutralization of Data within XPath Expressions (‘XPath Injection’)

CWE-643 – Improper Neutralization of Data within XPath Expressions (‘XPath Injection’)

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Description

The software uses external input to dynamically construct an XPath expression used to retrieve data from an XML database, but it does not neutralize or incorrectly neutralizes that input. This allows an attacker to control the structure of the query.

The net effect is that the attacker will have control over the information selected from the XML database and may use that ability to control application flow, modify logic, retrieve unauthorized data, or bypass important checks (e.g. authentication).

Modes of Introduction:

– Implementation

 

Likelihood of Exploit: High

 

Related Weaknesses

CWE-943
CWE-91

 

Consequences

Access Control: Bypass Protection Mechanism

Controlling application flow (e.g. bypassing authentication).

Confidentiality: Read Application Data

The attacker could read restricted XML content.

 

Potential Mitigations

Phase: Implementation

Description: 

Use parameterized XPath queries (e.g. using XQuery). This will help ensure separation between data plane and control plane.

Phase: Implementation

Description: 

Properly validate user input. Reject data where appropriate, filter where appropriate and escape where appropriate. Make sure input that will be used in XPath queries is safe in that context.

CVE References