CVE-2025-29774: Xml-crypto library vulnerability poses authentication and authorization issues

Xml-crypto is an XML digital signature and encryption library for Node.js, commonly used for securing data communication through signed XML documents. However, versions earlier than 6..1, 3.2.1, and 2.1.6 are now known to have a vulnerability that may allow attackers to bypass authentication or authorization mechanisms. This article dives into the details of this vulnerability, provides code snippets, and links to original references, along with recommendations on how to safeguard against the exploitation of this vulnerability.

Exploit Details

The vulnerability (CVE-2025-29774) allows attackers to modify valid signed XML messages while still passing signature verification checks. As a result, an attacker could potentially alter critical identity or access control attributes, enabling them to escalate privileges or impersonate another user. XML signature wrapping attacks accomplish this by introducing unauthenticated data into a signed XML message and tricking the signature verification process into accepting the malicious content.

Here's a code snippet illustrating the attacker's approach

// Original signed XML
<SignedInfo>
  <Reference URI="#ID1">
    <Transforms>
      <Transform Algorithm="...#enveloped-signature" />
    </Transforms>
    <DigestValue>12345</DigestValue>
  </Reference>
</SignedInfo>
<Object Id="ID1"> <!-- Real content -->
  <Data>UserA</Data>
</Object>

// Attacker injects fake content
<SignedInfo>
  <Reference URI="#ID1">
    <Transforms>
      <Transform Algorithm="...#enveloped-signature" />
    </Transforms>
    <DigestValue>12345</DigestValue>
  </Reference>
</SignedInfo>
<Object Id="ID1"> <!-- Real content -->
  <Data>UserA</Data>
</Object>
<Object Id="ID2"> <!-- Fake content -->
  <Data>UserB</Data>
</Object>

Further technical analysis and demonstration of the exploit can be found in the following articles

- GitHub Issue: XML Signature Bypass (Signature Wrapping Attack)
- XML Signature Wrapping (XSW) Explained

Affected Versions

All versions of xml-crypto prior to 6..1, 3.2.1, and 2.1.6 are affected by this vulnerability. If you are using any of these vulnerable versions, it's crucial to upgrade immediately.

Solution

To fix the vulnerability, it's recommended to upgrade to the latest version of xml-crypto, which is 6..1. If for any reason you are unable to upgrade to the latest version, you should at least upgrade to the patched versions 2.1.6 or 3.2.1 for their respective release branches.

To upgrade to the latest version of xml-crypto, you can use the following command

npm install xml-crypto@latest

To upgrade to the patched versions 2.1.6 or 3.2.1, you can use the following commands

npm install xml-crypto@2.1.6
npm install xml-crypto@3.2.1

Conclusion

The xml-crypto vulnerability (CVE-2025-29774) poses a serious threat to the authentication and authorization mechanisms of systems that rely on this library for verifying signed XML documents. By updating to the latest version (6..1) or the patched versions 2.1.6 or 3.2.1, you can safeguard your system against this vulnerability and reduce the risk of an attacker successfully exploiting it.

Timeline

Published on: 03/14/2025 17:15:52 UTC
Last modified on: 03/15/2025 21:15:35 UTC