CVE-2025-29775

Vulnerability Remediation/Mitigation Strategy: CVE-2025-29775 - XML Signature Bypass in xml-crypto

1. Vulnerability Description:

  • Name: CVE-2025-29775 - XML Signature Bypass in xml-crypto
  • Description: The xml-crypto library, used for XML digital signature and encryption in Node.js, contains a vulnerability that allows an attacker to bypass signature verification. This means a malicious actor can modify a legitimately signed XML document and the modified document will still be considered valid by systems using vulnerable versions of xml-crypto.
  • Affected Versions: Versions prior to 6.0.1, 3.2.1, and 2.1.6 are affected.
  • Root Cause: The specific details of the bypass are not explicitly provided in the advisory. However, vulnerabilities of this type usually involve weaknesses in the signature verification logic, such as insufficient canonicalization, improper handling of namespaces, or vulnerabilities in the underlying XML parsing libraries.

2. Severity:

  • CVSS Score: 9.3 (Critical)
  • Impact: High. This vulnerability can lead to:
    • Privilege Escalation: An attacker can modify access control attributes within the XML document, gaining elevated privileges.
    • Impersonation: An attacker can impersonate another user by altering identity information within the XML document.
    • Authentication Bypass: Systems relying on XML signatures for authentication can be completely bypassed.
    • Data Tampering: Critical data within the XML document can be altered without detection.

3. Known Exploit:

  • Exploitability: The advisory states that an attacker can modify a valid signed XML message in a way that still passes signature verification checks. While the exact details of the exploit are not provided, this indicates a practical and exploitable vulnerability exists. A proof-of-concept or exploit code is likely to emerge quickly after public disclosure.

4. Remediation/Mitigation Strategy:

This strategy focuses on immediate remediation steps, followed by a plan for longer-term improvements.

4.1 Immediate Remediation (Urgent Action Required):

  • Upgrade xml-crypto Library: This is the highest priority.
    • If using version 6.0.0 or prior: Upgrade to version 6.0.1 or later.
    • If using version 3.x: Upgrade to version 3.2.1 or later.
    • If using version 2.x: Upgrade to version 2.1.6 or later.
  • Verify Dependencies: Ensure that all applications and services using xml-crypto are upgraded. Use dependency management tools (e.g., npm audit, yarn audit, snyk, or similar tools for other package managers) to identify vulnerable dependencies.
  • Testing: After upgrading, thoroughly test all functionality that relies on XML signature verification to ensure the upgrade was successful and did not introduce any regressions. Specifically, test scenarios involving potentially malicious modifications to signed XML documents to confirm they are now correctly rejected.
  • Monitoring & Alerting: Implement monitoring for suspicious activity related to XML signature verification. This might involve logging and analyzing XML requests for unusual patterns or errors.
  • Incident Response Plan: Prepare an incident response plan in case of a successful exploit. This should include steps for identifying affected systems, containing the breach, and recovering compromised data.

4.2 Longer-Term Mitigation and Best Practices:

  • Implement Input Validation & Sanitization: Even after patching, add additional input validation and sanitization checks on the content of XML documents. Do not rely solely on the XML signature for security.
  • Code Review: Conduct thorough code reviews of all code that uses xml-crypto to ensure that the library is being used correctly and securely. Pay close attention to how XML documents are processed and verified.
  • Regular Dependency Audits: Implement automated and regular dependency audits to identify and address vulnerabilities in all dependencies, including xml-crypto and other security-sensitive libraries.
  • Consider Alternative Libraries: Evaluate alternative XML signature libraries for Node.js that may offer better security or be less prone to vulnerabilities. This could involve researching libraries with more robust signature verification implementations or those that are actively maintained and patched.
  • Principle of Least Privilege: Ensure that applications and users have only the minimum necessary permissions to access resources. This can limit the impact of a successful exploit.
  • Security Training: Provide security training to developers on secure coding practices related to XML processing and signature verification.

5. Communication:

  • Internal Communication: Communicate the vulnerability and the remediation plan to all relevant teams, including development, security, and operations.
  • External Communication (if applicable): If your application or service is used by external customers, consider notifying them of the vulnerability and providing guidance on how to protect themselves.

6. Verification:

  • After implementing the remediation steps, perform thorough verification to ensure that the vulnerability has been successfully addressed. This includes:
    • Verifying the upgraded versions of xml-crypto are in place.
    • Re-running any existing security tests to confirm the vulnerability is no longer present.
    • Conducting penetration testing to simulate a real-world attack and identify any remaining weaknesses.

Example Code (Illustrative - Actual implementation details will depend on your specific application): javascript // Vulnerable Code (Example - Prior to upgrade) const { SignedXml } = require(‘xml-crypto’); const fs = require(‘fs’);

// Load the XML document and signature const xml = fs.readFileSync(‘signed.xml’, ‘utf8’); const signature = fs.readFileSync(‘signature.xml’, ‘utf8’);

const sig = new SignedXml(); sig.loadSignature(signature); sig.loadXml(xml);

const isValid = sig.checkSignature(); // Vulnerable line console.log(‘Signature is valid:’, isValid);

// Fixed Code (Example - After upgrade) const { SignedXml } = require(‘xml-crypto’); const fs = require(‘fs’);

// Load the XML document and signature const xml = fs.readFileSync(‘signed.xml’, ‘utf8’); const signature = fs.readFileSync(‘signature.xml’, ‘utf8’);

const sig = new SignedXml(); sig.loadSignature(signature); sig.loadXml(xml);

//In a real world scenario, you would implement your key providers //This shows an example of how to use a static public key. const publicKey = fs.readFileSync(‘public_key.pem’, ‘utf8’);

//The ‘checkSignature’ method no longer takes a key parameter. const isValid = sig.checkSignature(publicKey); //Fixed. console.log(‘Signature is valid:’, isValid);

//More secure and robust implementations often require specific key information, //algorithm constraints, and other validations.

Disclaimer: This remediation strategy provides general guidance. The specific steps required to address this vulnerability may vary depending on your specific environment and application. Consult with security experts and refer to the official documentation for xml-crypto for more detailed information. Continuously monitor for new information and updates related to this vulnerability.

Assigner

Date

  • Published Date: 2025-03-14 17:11:06
  • Updated Date: 2025-03-15 21:15:35

More Details

CVE-2025-29775