CVE-2012-0146 in Forefront Unified Access Gateway
Summary
by MITRE
Open redirect vulnerability in Microsoft Forefront Unified Access Gateway (UAG) 2010 SP1 and SP1 Update 1 allows remote attackers to redirect users to arbitrary web sites and conduct phishing attacks via a crafted URL, aka "UAG Blind HTTP Redirect Vulnerability."
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Analysis
by VulDB Data Team • 12/01/2021
The CVE-2012-0146 vulnerability represents a critical open redirect flaw in Microsoft Forefront Unified Access Gateway 2010 SP1 and SP1 Update 1 deployments. This vulnerability specifically affects the authentication and access control mechanisms within the UAG platform, which serves as a unified access gateway for enterprise environments. The flaw enables malicious actors to manipulate the redirect functionality that is typically used for legitimate authentication flows, creating a pathway for unauthorized redirection of users to attacker-controlled web resources. The vulnerability operates at the application layer and exploits the trust relationship between the gateway and end users during authentication processes, making it particularly dangerous in enterprise settings where sensitive data flows through these access points.
The technical implementation of this vulnerability stems from insufficient validation of redirect URLs within the UAG authentication handling code. When users attempt to access protected resources through the gateway, the system processes redirect parameters that are not properly sanitized or validated against a whitelist of approved destinations. This allows attackers to craft malicious URLs containing crafted redirect parameters that bypass normal access controls and direct users to phishing sites or malicious web resources. The flaw essentially creates a blind redirect mechanism where the system automatically forwards users without proper verification of the destination, making it particularly challenging to detect and prevent through traditional security measures. The vulnerability aligns with CWE-601 Open Redirect vulnerability classification, which specifically addresses situations where applications redirect users to external domains without proper validation.
The operational impact of this vulnerability extends beyond simple phishing attacks, as it can enable more sophisticated social engineering campaigns and credential theft operations. Attackers can leverage this vulnerability to create convincing phishing pages that appear legitimate within the enterprise context, since the initial redirect originates from a trusted UAG system. The attack vector is particularly effective because it operates at the perimeter of enterprise networks where users expect secure authentication flows. Organizations may experience unauthorized access to sensitive systems, data exfiltration through credential theft, and potential compromise of the entire network infrastructure. The vulnerability can also facilitate lateral movement within networks if attackers use the redirected sessions to access internal resources that would otherwise be protected by proper access controls.
Mitigation strategies for CVE-2012-0146 should focus on immediate patching of affected UAG systems, implementing strict URL validation mechanisms, and establishing network-level controls to monitor and block suspicious redirect traffic. Microsoft released security updates for this vulnerability, and organizations should prioritize applying these patches to prevent exploitation. Network administrators should also implement web application firewalls that can detect and block malicious redirect patterns, while security teams should monitor authentication logs for unusual redirect activities. The vulnerability demonstrates the importance of proper input validation and the principle of least privilege in access control systems, aligning with ATT&CK technique T1566 for Phishing and T1071 for Application Layer Protocol usage. Organizations should also consider implementing additional authentication controls such as multi-factor authentication to reduce the impact if redirection attacks are successfully executed, as this vulnerability primarily affects the initial authentication phase of user sessions.