CVE-2017-11429 in saml2-js
Summary
by MITRE
Clever saml2-js 2.0 and earlier may incorrectly utilize the results of XML DOM traversal and canonicalization APIs in such a way that an attacker may be able to manipulate the SAML data without invalidating the cryptographic signature, allowing the attack to potentially bypass authentication to SAML service providers.
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Analysis
by VulDB Data Team • 08/29/2023
The vulnerability identified as CVE-2017-11429 affects the clever saml2-js library version 2.0 and earlier, presenting a critical security flaw in SAML authentication implementations. This issue stems from improper handling of XML DOM traversal and canonicalization operations within the library's signature verification process, creating a fundamental weakness in the cryptographic integrity checks that protect SAML assertions. The vulnerability specifically targets the way the library processes XML data structures during signature validation, allowing malicious actors to manipulate SAML content while maintaining the appearance of valid cryptographic signatures.
The technical root cause of this vulnerability lies in the library's failure to properly validate the XML canonicalization process and DOM traversal results when verifying SAML signatures. According to CWE-347, this represents a weakness in cryptographic signature verification where the system fails to properly validate the integrity of the signed data. The flaw enables attackers to perform signature wrapping attacks or XML canonicalization attacks by manipulating the XML structure in ways that do not invalidate the existing cryptographic signature. This occurs because the library does not adequately verify that the XML data being signed matches exactly with the data being validated during the signature process.
From an operational perspective, this vulnerability creates a severe authentication bypass risk for any system utilizing the affected saml2-js library. Attackers can manipulate SAML assertions to gain unauthorized access to protected resources without detection, as the cryptographic signature validation appears to succeed despite the data manipulation. The impact extends beyond simple privilege escalation to potentially enable complete system compromise, especially when combined with other attack vectors. Organizations relying on SAML-based authentication systems are particularly vulnerable since this flaw affects the core integrity validation mechanisms that protect against tampered authentication data.
The attack surface for this vulnerability aligns with ATT&CK technique T1550.001, which involves using legitimate credentials to gain access to systems, particularly in the context of SAML authentication bypasses. Security practitioners should consider this vulnerability as part of a broader authentication bypass attack chain where attackers leverage signature validation weaknesses to manipulate authentication flows. The remediation approach requires immediate library updates to versions that properly implement XML canonicalization and DOM traversal validation, along with thorough testing of all SAML integration points. Organizations should also implement monitoring for suspicious authentication patterns and consider additional signature validation layers as defensive measures against similar vulnerabilities in other XML-based security implementations.