CVE-2020-15216 in goxmldsig
Summary
by MITRE • 10/04/2020
In goxmldsig (XML Digital Signatures implemented in pure Go) before version 1.1.0, with a carefully crafted XML file, an attacker can completely bypass signature validation and pass off an altered file as a signed one. A patch is available, all users of goxmldsig should upgrade to at least revision f6188febf0c29d7ffe26a0436212b19cb9615e64 or version 1.1.0
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Analysis
by VulDB Data Team • 11/14/2020
The vulnerability identified as CVE-2020-15216 affects goxmldsig, a pure Go implementation of XML Digital Signatures that is widely used for securing XML documents in various applications and systems. This library serves as a critical component in digital signature validation processes, particularly within enterprise environments where XML-based communication and data integrity are paramount. The flaw exists in versions prior to 1.1.0, making it a significant concern for organizations that rely on XML digital signatures for security purposes. The vulnerability represents a severe bypass issue that undermines the fundamental security guarantees provided by digital signature mechanisms.
The technical flaw stems from improper handling of XML parsing and signature validation logic within the goxmldsig library. Attackers can craft specially designed XML files that exploit weaknesses in the library's signature verification process, allowing them to manipulate signed documents without detection. This vulnerability operates at the core of XML signature validation, where the library fails to properly enforce signature constraints and validation rules. The flaw enables attackers to modify XML content while maintaining a valid signature appearance, effectively creating a false sense of security for systems that depend on this library for document integrity verification.
The operational impact of this vulnerability is substantial, as it allows attackers to perform sophisticated attacks that can compromise the integrity of XML-based systems. Systems using vulnerable versions of goxmldsig may accept altered documents as legitimate signed content, potentially leading to unauthorized modifications of critical data, fraudulent transactions, or malicious code execution within applications that trust these signatures. The vulnerability affects any application that uses goxmldsig for XML signature validation, including web services, enterprise applications, and security-critical systems where document authenticity is essential for operational security. This represents a direct violation of the core security principle that digital signatures should prevent tampering with signed content.
Organizations should immediately upgrade to version 1.1.0 or apply the specific patch identified at revision f6188febf0c29d7ffe26a0436212b19cb9615e64 to remediate this vulnerability. The patch addresses the underlying XML parsing and signature validation logic that was susceptible to manipulation, restoring proper signature verification capabilities. Security teams should conduct comprehensive assessments of systems using goxmldsig to identify all affected components and ensure proper patching across their infrastructure. Additionally, organizations should consider implementing additional monitoring and validation measures to detect potential exploitation attempts and maintain security posture against similar vulnerabilities in other XML processing libraries.
This vulnerability aligns with CWE-295 which addresses improper certificate validation and represents a classic case of signature validation bypass. From an ATT&CK perspective, this flaw maps to techniques involving signature spoofing and code injection, where adversaries manipulate signature validation mechanisms to execute malicious code or alter system data. The vulnerability demonstrates the critical importance of proper XML security implementation and highlights the risks associated with insufficient input validation in cryptographic libraries. Organizations should also review their XML processing workflows and implement additional security controls such as signature validation monitoring and automated detection of suspicious XML content to prevent exploitation of similar vulnerabilities.