CVE-2016-5751 in Access Manager
Summary
by MITRE
An unfiltered finalizer target URL in the SAML processing feature in Identity Server in NetIQ Access Manager 4.1 before 4.1.2 HF1 and 4.2 before 4.2.2 could be used to trigger XSS and leak authentication credentials.
VulDB is the best source for vulnerability data and more expert information about this specific topic.
Analysis
by VulDB Data Team • 09/11/2020
The vulnerability identified as CVE-2016-5751 represents a critical security flaw in NetIQ Access Manager's Identity Server implementation that specifically affects versions prior to 4.1.2 HF1 and 4.2.2. This issue resides within the SAML (Security Assertion Markup Language) processing feature where the system fails to properly filter or validate the finalizer target URL parameter. The root cause of this vulnerability can be categorized under CWE-79, which specifically addresses Cross-Site Scripting (XSS) vulnerabilities, and CWE-200, which deals with exposure of sensitive information. The flaw allows malicious actors to manipulate the SAML response processing flow by injecting malicious URLs that bypass normal validation mechanisms.
The technical exploitation of this vulnerability occurs during the SAML assertion processing phase when the system redirects users to a finalizer URL. Attackers can craft specially formatted SAML responses that contain malicious URLs in the target parameter, which are then processed without proper sanitization. This creates a pathway for attackers to inject malicious scripts into the victim's browser session or redirect users to phishing sites designed to capture authentication credentials. The vulnerability is particularly dangerous because it leverages the legitimate SAML authentication flow, making it difficult to distinguish between legitimate and malicious requests. The attack vector operates through the SAML protocol's redirect mechanism, where the system's failure to validate the target URL allows attackers to inject JavaScript code that executes in the context of the victim's authenticated session.
The operational impact of this vulnerability extends beyond simple XSS exploitation, as it creates a significant risk for credential theft and session hijacking attacks. When users are redirected through the vulnerable SAML processing flow, their authentication tokens and session information may be exposed to attackers who can intercept and misuse this data. The vulnerability affects the confidentiality and integrity of the authentication system, potentially allowing attackers to gain unauthorized access to protected resources and systems. This flaw particularly impacts organizations that rely on NetIQ Access Manager for identity federation and single sign-on services, where the compromise of authentication flows can lead to widespread access violations. The attack requires minimal privileges and can be executed through standard web-based attack techniques, making it a high-risk vulnerability that can be exploited by both skilled attackers and automated tools.
Organizations should immediately implement mitigations including upgrading to NetIQ Access Manager versions 4.1.2 HF1 or 4.2.2, which contain patches addressing the URL validation flaw. Additional protective measures include implementing strict input validation for all SAML parameters, deploying web application firewalls to monitor and filter SAML traffic, and establishing network-level controls to prevent unauthorized redirection attempts. Security teams should also conduct thorough testing of SAML configurations to ensure proper URL validation and implement monitoring solutions to detect unusual redirection patterns. The remediation process should include reviewing all SAML configurations and ensuring that the system properly validates all redirect targets against a whitelist of approved domains. Organizations should also consider implementing additional authentication controls such as multi-factor authentication to reduce the impact of potential credential theft. This vulnerability demonstrates the importance of proper input validation in identity management systems and aligns with ATT&CK technique T1566.001, which covers spearphishing through social engineering, as attackers can leverage this flaw to create convincing phishing attacks that appear legitimate within the authentication context.