CVE-2023-34205 in signedxml
Summary
by MITRE • 05/30/2023
In Moov signedxml through 1.0.0, parsing the raw XML (as received) can result in different output than parsing the canonicalized XML. Thus, signature validation can be bypassed via a Signature Wrapping attack (aka XSW).
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Analysis
by VulDB Data Team • 07/13/2025
The vulnerability identified as CVE-2023-34205 affects the Moov signedxml library version 1.0.0 and earlier, presenting a significant security risk through signature wrapping attacks. This flaw stems from inconsistent XML parsing behavior between raw and canonicalized XML processing, creating a vector for malicious actors to bypass digital signature validation mechanisms. The issue specifically impacts systems relying on XML signature verification for security assurance, potentially allowing unauthorized modifications to signed documents without detection.
The technical root cause lies in the library's handling of XML canonicalization processes where the raw XML parsing produces different results compared to canonicalized XML parsing. This inconsistency creates a scenario where attackers can craft malicious XML documents that pass signature validation when processed through the raw parsing path but would fail when processed through the canonicalized path. The vulnerability enables what is known as a signature wrapping attack, where an attacker can wrap a valid signature around malicious content, effectively bypassing the intended security controls. This represents a classic implementation flaw in XML security processing that violates fundamental security assumptions about signature validation consistency.
From an operational impact perspective, this vulnerability compromises the integrity and authenticity guarantees that XML signatures are designed to provide. Systems utilizing the affected Moov signedxml library may experience unauthorized data modification, document tampering, or fraudulent transactions that appear legitimate due to passing signature validation. The attack vector is particularly concerning because it operates at the signature validation layer, meaning that security controls relying on XML signatures for authentication or data integrity verification become ineffective. This vulnerability directly undermines trust in digital signatures and could lead to significant financial losses, regulatory violations, and reputational damage for affected organizations.
The security implications align with CWE-347, which addresses improper certificate validation, and relates to ATT&CK technique T1556.004 for credential access through signature validation bypasses. Organizations should immediately update to patched versions of the Moov signedxml library, implement additional signature validation checks, and monitor for potential exploitation attempts. Network segmentation and access controls should be reinforced to limit potential attack surfaces, while security teams should conduct thorough audits of systems using this library to identify and remediate any potential exploitation. The vulnerability demonstrates the critical importance of consistent canonicalization behavior in XML security implementations and highlights the need for comprehensive testing of security-critical XML processing functions.