CVE-2012-4777 in .NET Framework
Summary
by MITRE
The code-optimization feature in the reflection implementation in Microsoft .NET Framework 4 and 4.5 does not properly enforce object permissions, which allows remote attackers to execute arbitrary code via (1) a crafted XAML browser application (aka XBAP) or (2) a crafted .NET Framework application, aka "WPF Reflection Optimization Vulnerability."
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Analysis
by VulDB Data Team • 04/19/2021
The CVE-2012-4777 vulnerability represents a critical security flaw in Microsoft .NET Framework versions 4 and 4.5 that specifically targets the reflection implementation's code-optimization feature. This vulnerability stems from improper enforcement of object permissions within the Windows Presentation Foundation (WPF) framework, creating a pathway for remote code execution attacks. The flaw exists in how the .NET runtime handles reflection optimization when processing certain types of applications, particularly those leveraging XAML browser applications or standard .NET applications that utilize reflection mechanisms. The vulnerability is particularly concerning because it can be exploited through multiple attack vectors, making it a significant threat to enterprise environments that rely on .NET Framework applications.
The technical root cause of this vulnerability lies in the interaction between the .NET Framework's reflection optimization subsystem and the security boundaries that should normally prevent unauthorized code execution. When the framework processes reflection operations in optimized code paths, it fails to properly validate permission levels for objects that are being accessed through reflection mechanisms. This allows malicious actors to craft specific XAML browser applications or .NET applications that can bypass standard security restrictions. The vulnerability specifically affects the WPF component of .NET Framework, where reflection optimization is used to improve performance but inadvertently creates a security loophole. According to CWE classification, this vulnerability maps to CWE-284: Improper Access Control, as it involves inadequate permission checking during reflection operations.
The operational impact of CVE-2012-4777 is severe and far-reaching across enterprise environments that utilize .NET Framework applications. Attackers can exploit this vulnerability remotely to execute arbitrary code with the privileges of the affected application, potentially leading to complete system compromise. The vulnerability affects both XAML browser applications and standard .NET applications, expanding the attack surface significantly. Organizations running web applications, desktop applications, or services that depend on .NET Framework 4 or 4.5 are at risk, particularly those with less stringent network segmentation. The attack vectors include malicious XBAP files that can be delivered through web browsers or crafted .NET applications that can be executed in trusted environments where reflection operations are performed. This vulnerability aligns with ATT&CK technique T1059.001: Command and Scripting Interpreter, as it enables attackers to execute arbitrary code through legitimate system interfaces.
Mitigation strategies for CVE-2012-4777 primarily involve applying Microsoft's security patches and updates that address the underlying permission enforcement issues in the .NET Framework reflection optimization feature. Organizations should immediately deploy the relevant security updates from Microsoft, specifically targeting the .NET Framework 4 and 4.5 versions. Additionally, implementing network segmentation and access controls can help limit the potential impact of successful exploitation attempts. Security administrators should also consider disabling unnecessary reflection operations in applications where possible, though this may impact application functionality. The vulnerability demonstrates the importance of proper security testing for performance optimization features, as the code-optimization mechanisms inadvertently created security weaknesses. Organizations should conduct thorough vulnerability assessments of their .NET Framework applications to identify potential exposure and implement appropriate security controls. This vulnerability also underscores the need for comprehensive security testing throughout the software development lifecycle, particularly for features that interact with system-level operations such as reflection and code generation.