COMMON WEAKNESS ENUMERATIONIncomplete

CWE-643

Improper Neutralization of Data within XPath Expressions ('XPath Injection')

The product 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.

Abstraction

Base

Structure

Simple

Likelihood of Exploit

High

Understand the problem

What is the problem?

The product 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.

Extended description

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).

Root cause

How and when does the problem arise?

Lifecycle phase

Implementation

REALIZATION: This weakness is caused during implementation of an architectural security tactic.

Risk

What does successful exploitation lead to?

Bypass Protection Mechanism

Affected security scopes: Access Control

Controlling application flow (e.g. bypassing authentication).
Read Application Data

Affected security scopes: Confidentiality

The attacker could read restricted XML content.

Defence

How is it prevented and fixed?

Implementation

Implementation-phase defence

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

Implementation

Implementation-phase defence

Detail
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.

Verification

How is it detected?

Automated Static Analysis

High
Automated static analysis, commonly referred to as Static Application Security Testing (SAST), can find some instances of this weakness by analyzing source code (or binary/compiled code) without having to execute it. Typically, this is done by building a model of data flow and control flow, then searching for potentially-vulnerable patterns that connect "sources" (origins of input) with "sinks" (destinations where the data interacts with external components, a lower layer such as the OS, etc.)
CWE-643: Common Weakness Enumeration Entry CWE-643 · DayBreach Sözlük · DayBreach