CVE-2012-1896 in .NET Framework
Summary
by MITRE
Microsoft .NET Framework 2.0 SP2 and 3.5.1 does not properly consider trust levels during construction of output data, which allows remote attackers to obtain sensitive information via (1) a crafted XAML browser application (aka XBAP) or (2) a crafted .NET Framework application, aka "Code Access Security Info Disclosure Vulnerability."
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Analysis
by VulDB Data Team • 04/19/2021
The vulnerability identified as CVE-2012-1896 represents a critical weakness in Microsoft .NET Framework versions 2.0 SP2 and 3.5.1 that fundamentally undermines the security model designed to protect applications from unauthorized access to sensitive data. This flaw resides within the Code Access Security (CAS) framework, which is intended to enforce security boundaries and restrict what applications can access based on their trust levels. The vulnerability specifically manifests when the framework fails to properly evaluate trust levels during the construction of output data, creating an avenue for attackers to bypass security restrictions.
The technical exploitation of this vulnerability occurs through two primary vectors that leverage different aspects of the .NET Framework's security model. The first vector involves crafting malicious XAML browser applications, also known as XBAPs, which are designed to run within web browsers and can execute with elevated privileges when improperly sandboxed. The second vector targets standard .NET Framework applications that may be manipulated to exploit the trust level evaluation process. Both attack methods exploit the same underlying flaw where the framework's output data construction process does not adequately validate or enforce the trust boundaries that should prevent unauthorized data access. This weakness enables attackers to potentially extract sensitive information that should normally be restricted based on the application's security context.
The operational impact of this vulnerability extends beyond simple information disclosure, as it fundamentally compromises the integrity of the Code Access Security model that Microsoft designed to protect against malicious code execution. Attackers who successfully exploit this vulnerability can potentially access sensitive data that should be protected by the trust level restrictions, including system resources, user information, and application-specific data that may contain confidential or proprietary information. The vulnerability affects both client-side applications and web-hosted applications, making it particularly dangerous in enterprise environments where .NET Framework applications are widely deployed. This exposure creates potential risks for data breaches and unauthorized access to critical systems that rely on .NET Framework security boundaries.
The vulnerability maps directly to CWE-200, which addresses "Information Exposure," and demonstrates how improper handling of security contexts can lead to unauthorized data access. From an ATT&CK framework perspective, this vulnerability aligns with T1059, "Command and Scripting Interpreter," and T1068, "Exploitation for Privilege Escalation," as attackers can leverage the information disclosure to gain further access to system resources. Organizations should implement immediate mitigations including applying the relevant Microsoft security patches, reviewing and tightening Code Access Security policies, and monitoring for suspicious application behavior. Additionally, administrators should consider implementing network segmentation to limit the potential impact of successful exploitation and ensure that .NET Framework applications are running with the minimum necessary privileges to reduce the attack surface. The vulnerability highlights the critical importance of maintaining up-to-date security patches and proper security configuration management in enterprise environments relying on Microsoft technologies.