CVE-2012-1855 in .NET Framework
Summary
by MITRE
Microsoft .NET Framework 2.0 SP2, 3.5, 3.5.1, 4, and 4.5 does not properly handle function pointers, 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 ".NET Framework Memory Access Vulnerability."
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Analysis
by VulDB Data Team • 01/02/2025
The vulnerability identified as CVE-2012-1855 represents a critical memory access flaw within Microsoft .NET Framework versions 2.0 SP2 through 4.5 that fundamentally compromises the security boundaries of the runtime environment. This issue arises from improper handling of function pointers during the execution of managed code, creating a pathway for malicious actors to bypass the security model that normally isolates application code from system resources. The vulnerability specifically affects the .NET Framework's memory management mechanisms, where function pointers are not adequately validated or sanitized before being processed, leading to potential arbitrary code execution.
The technical exploitation of this vulnerability occurs through two primary vectors that leverage different attack surfaces within the .NET Framework ecosystem. The first vector involves crafted XAML browser applications, commonly known as XBAPs, which are rich internet applications that run within web browsers and can execute with elevated privileges when properly configured. These applications present a unique attack surface because they can be loaded directly from web servers and execute within the browser context with access to the underlying .NET Framework runtime. The second vector targets traditional .NET Framework applications that may be designed to handle untrusted input or dynamically loaded code, where attackers can manipulate function pointer references to gain unauthorized access to memory locations. Both attack vectors exploit the fundamental flaw in how the framework processes function pointers, allowing attackers to manipulate memory access patterns and execute malicious code with the privileges of the running application.
The operational impact of this vulnerability extends beyond simple code execution, as it can enable attackers to perform a wide range of malicious activities that would normally be restricted by the .NET Framework's security model. When successfully exploited, the vulnerability can allow remote code execution with the privileges of the user running the affected application, potentially leading to complete system compromise if the application runs with elevated privileges. Attackers could leverage this vulnerability to install backdoors, steal sensitive data, modify system configurations, or establish persistent access to compromised systems. The vulnerability is particularly concerning because it affects multiple versions of the .NET Framework, meaning that organizations with legacy systems or applications that have not been updated could remain vulnerable for extended periods. Additionally, the nature of function pointer manipulation means that the attack could potentially bypass traditional security controls such as code signing verification and application sandboxing mechanisms that are designed to prevent unauthorized code execution.
Organizations affected by this vulnerability should implement immediate mitigations including applying the relevant Microsoft security patches that address the memory access handling issues within the .NET Framework runtime. The recommended approach involves updating all systems to the latest .NET Framework versions that contain the necessary fixes for function pointer validation and memory management. Network segmentation and application whitelisting can provide additional defensive layers by limiting the attack surface and preventing unauthorized applications from executing on critical systems. Security monitoring should be enhanced to detect anomalous memory access patterns or unexpected code execution behaviors that could indicate exploitation attempts. The vulnerability aligns with CWE-122, which describes buffer overflow conditions where memory access is not properly validated, and relates to ATT&CK technique T1059.001 for command and script injection through .NET Framework applications. Organizations should also consider implementing runtime application self-protection mechanisms and regular security assessments to identify and remediate similar vulnerabilities in their software ecosystems.