CVE-2017-11430 in OmnitAuth-SAML
Summary
by MITRE
OmniAuth OmnitAuth-SAML 1.9.0 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 • 09/20/2024
The vulnerability identified as CVE-2017-11430 affects OmniAuth OmnitAuth-SAML versions 1.9.0 and earlier, presenting a critical security flaw in the handling of SAML authentication processes. This issue stems from improper utilization of XML DOM traversal and canonicalization APIs within the SAML implementation, creating a pathway for attackers to manipulate SAML data while maintaining the validity of cryptographic signatures. The flaw specifically impacts SAML service providers that rely on this authentication mechanism, potentially allowing unauthorized access to protected resources.
The technical root cause of this vulnerability lies in how the software processes XML canonicalization operations during SAML message validation. When XML documents are processed through DOM traversal methods, the system fails to properly validate the canonicalization results, enabling attackers to craft modified SAML assertions that appear legitimate to the service provider. This weakness operates at the intersection of XML security processing and cryptographic signature verification, where the canonicalization process should ensure consistent representation of XML data for signature validation but instead allows for manipulation that preserves signature integrity.
From an operational perspective, this vulnerability creates a significant risk for organizations relying on SAML-based single sign-on implementations. Attackers can exploit this flaw to modify SAML assertion data such as user identity claims, roles, or permissions without detection, potentially gaining elevated access privileges or bypassing authentication entirely. The impact extends beyond simple credential theft to include privilege escalation and unauthorized system access, particularly affecting cloud services and enterprise applications that depend on SAML for authentication. This vulnerability directly relates to CWE-295, which addresses improper certificate validation, and CWE-347, concerning improper verification of cryptographic signatures.
The attack vector for this vulnerability involves manipulating SAML assertions through XML canonicalization manipulation techniques that preserve signature validity. Attackers can leverage this weakness to alter user attributes, change authentication status, or modify access controls within the SAML response, all while maintaining the cryptographic signature that should validate the assertion's authenticity. This represents a sophisticated attack pattern that combines XML processing flaws with cryptographic verification bypass techniques, making it particularly dangerous for enterprise environments where SAML is widely deployed for identity management and access control.
Organizations should immediately implement mitigations including updating to OmniAuth OmnitAuth-SAML version 1.10.0 or later, which contains the necessary fixes for this vulnerability. Additional protective measures include implementing comprehensive SAML message validation controls, monitoring for unusual authentication patterns, and conducting regular security assessments of identity federation components. The remediation approach should align with ATT&CK technique T1550.001, focusing on credential access prevention through proper validation mechanisms. Security teams should also consider implementing network-level controls to detect and prevent manipulation of SAML assertions, as well as establishing robust logging and monitoring for authentication events that could indicate exploitation attempts.