CVE-2016-5752 in Access Manager
Summary
by MITRE
The SAML2 implementation in Identity Server in NetIQ Access Manager 4.1 before 4.1.2 HF1 and 4.2 before 4.2.2 was handling unsigned SAML requests incorrectly, leaking results to a potentially malicious "Assertion Consumer Service URL" instead of the original requester.
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Analysis
by VulDB Data Team • 09/11/2020
The vulnerability identified as CVE-2016-5752 represents a critical flaw in the Security Assertion Markup Language 2.0 implementation within NetIQ Access Manager's Identity Server components. This issue affects versions 4.1 before 4.1.2 HF1 and 4.2 before 4.2.2, where the system fails to properly validate SAML request signatures. The flaw stems from improper handling of unsigned SAML requests, creating a significant security gap that allows unauthorized parties to manipulate the authentication flow. When unsigned SAML requests are processed, the system incorrectly routes the authentication results to a malicious Assertion Consumer Service URL rather than the legitimate requester, effectively bypassing the intended security controls.
The technical nature of this vulnerability falls under CWE-347, which addresses improper verification of cryptographic signatures, and represents a failure in the SAML protocol implementation that violates fundamental security principles. The flaw operates by exploiting the trust relationship between the Identity Provider and Service Provider components, where the system's inadequate signature validation allows attackers to redirect authentication responses to arbitrary endpoints. This misconfiguration creates an opportunity for man-in-the-middle attacks, session hijacking, and potential credential theft, as the system fails to verify that the SAML response originates from a legitimate source.
From an operational perspective, this vulnerability exposes organizations to significant risk during authentication processes, particularly when users attempt to access protected resources through the affected NetIQ Access Manager instances. The impact extends beyond simple authentication bypass, as it allows attackers to intercept and potentially manipulate sensitive authentication data, including user credentials and session tokens. Attackers can leverage this flaw to redirect users to malicious endpoints, creating opportunities for phishing attacks, credential harvesting, and unauthorized access to corporate resources. The vulnerability particularly affects environments where NetIQ Access Manager serves as a central authentication hub for multiple applications and services.
Mitigation strategies for CVE-2016-5752 should prioritize immediate deployment of the vendor-provided security patches, specifically the hotfixes for versions 4.1.2 HF1 and 4.2.2. Organizations should also implement additional monitoring to detect unusual patterns in SAML request processing and Assertion Consumer Service URL redirections. Network-level controls including firewalls and intrusion detection systems should be configured to restrict access to the affected components and monitor for suspicious SAML traffic patterns. The implementation of proper cryptographic signature validation should be enforced across all SAML exchanges, ensuring that unsigned requests are rejected and that all authentication responses are properly authenticated before being processed. Additionally, security teams should conduct comprehensive vulnerability assessments to identify any other potentially affected systems and establish robust logging mechanisms to detect exploitation attempts. This vulnerability aligns with ATT&CK technique T1566, which covers credential harvesting through social engineering, and represents a significant risk to identity and access management systems that rely on SAML-based authentication protocols.