CVE-2025-29775 in xml-crypto
Summary
by MITRE • 03/14/2025
xml-crypto is an XML digital signature and encryption library for Node.js. An attacker may be able to exploit a vulnerability in versions prior to 6.0.1, 3.2.1, and 2.1.6 to bypass authentication or authorization mechanisms in systems that rely on xml-crypto for verifying signed XML documents. The vulnerability allows an attacker to modify a valid signed XML message in a way that still passes signature verification checks. For example, it could be used to alter critical identity or access control attributes, enabling an attacker to escalate privileges or impersonate another user. Users of versions 6.0.0 and prior should upgrade to version 6.0.1 to receive a fix. Those who are still using v2.x or v3.x should upgrade to patched versions 2.1.6 or 3.2.1, respectively.
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Analysis
by VulDB Data Team • 03/14/2025
The xml-crypto library vulnerability represents a critical flaw in XML digital signature verification mechanisms that affects multiple major versions including 2.x, 3.x, and 6.x series. This vulnerability falls under the category of signature forgery or validation bypass, where an attacker can manipulate signed XML documents without breaking the cryptographic signature verification process. The flaw specifically impacts systems that rely on xml-crypto for authenticating XML-based communications, particularly in enterprise environments where identity management and access control are implemented through XML signatures. The vulnerability exists in the library's handling of XML canonicalization and signature validation algorithms, creating a window for attackers to modify document content while maintaining valid signatures.
The technical implementation of this vulnerability stems from improper handling of XML canonicalization processes and insufficient validation of signature structures within the xml-crypto library. Attackers can exploit this by crafting malicious XML documents that contain modified content but still pass verification checks due to weaknesses in how the library processes and validates the XML structure. This allows for the alteration of critical attributes such as user identities, permissions, or access control information within signed XML documents. The vulnerability specifically affects the signature verification logic, enabling attackers to perform privilege escalation attacks by modifying access control elements while preserving the document's validity. This type of flaw is categorized as CWE-347 - Improper Verification of Cryptographic Signature and aligns with ATT&CK technique T1556.004 - Modify Authentication Process which focuses on manipulating authentication mechanisms.
The operational impact of this vulnerability extends beyond simple authentication bypass to potentially enable complete system compromise in environments relying on XML-based security mechanisms. Organizations using xml-crypto for security-critical applications such as SAML assertions, WS-Security tokens, or enterprise identity management systems face significant risk of unauthorized access and privilege escalation. The vulnerability can be exploited across various attack vectors including man-in-the-middle scenarios, compromised service accounts, or insider threats where attackers have access to signed XML communications. Systems utilizing this library for API authentication, single sign-on implementations, or secure message exchanges are particularly vulnerable to this type of attack. The attack surface is broad given that xml-crypto is commonly used in enterprise security frameworks and web services requiring XML signature validation.
Mitigation strategies for this vulnerability require immediate version upgrades to patched releases including 6.0.1, 3.2.1, and 2.1.6 respectively. Organizations should conduct comprehensive inventory assessments to identify all systems utilizing affected versions of xml-crypto and implement mandatory upgrade procedures. Security teams should also consider implementing additional monitoring for suspicious XML document modifications and signature validation failures. The fix addresses the core canonicalization and validation logic issues that allowed attackers to bypass signature verification checks. Organizations should perform thorough regression testing after upgrading to ensure that legitimate XML document processing continues to function correctly. Additional defensive measures include implementing network segmentation for systems handling XML signatures, deploying signature validation monitoring tools, and establishing incident response procedures for potential exploitation attempts. This vulnerability highlights the importance of maintaining up-to-date cryptographic libraries and implementing proper security testing for authentication mechanisms.