CVE-2012-0161 in .NET Framework
Summary
by MITRE
Microsoft .NET Framework 1.0 SP3, 1.1 SP1, 2.0 SP2, 3.0 SP2, 3.5 SP1, 3.5.1, and 4 does not properly handle an unspecified exception during use of partially trusted assemblies to serialize input data, 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 Serialization Vulnerability."
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Analysis
by VulDB Data Team • 03/24/2021
The CVE-2012-0161 vulnerability represents a critical serialization flaw within Microsoft .NET Framework versions spanning from 1.0 SP3 through 4.0, where the framework fails to properly handle exceptions during the serialization process of input data when partially trusted assemblies are involved. This vulnerability operates at the core of .NET's security model, specifically targeting the interaction between trust levels and serialization mechanisms that are fundamental to application data handling and communication. The flaw manifests when the framework processes serialized data through partially trusted code contexts, creating an exploitable condition that can be leveraged by malicious actors to bypass security restrictions and execute arbitrary code remotely.
The technical nature of this vulnerability stems from improper exception handling within the .NET Framework's serialization subsystem, particularly when dealing with XAML browser applications and .NET Framework applications that utilize partially trusted code execution environments. The vulnerability is classified under CWE-248, which addresses "Uncaught Exception" conditions, and operates as an exploit against the framework's trust boundary mechanisms. When a maliciously crafted XAML browser application or .NET application attempts to serialize data through partially trusted assemblies, the framework's exception handling logic fails to properly secure the execution context, allowing attackers to escalate privileges and execute arbitrary code with the privileges of the executing process.
The operational impact of this vulnerability extends beyond simple code execution, as it enables attackers to bypass the fundamental security model of .NET Framework applications. Attackers can craft malicious XBAP applications or .NET Framework applications that exploit the serialization flaw to gain unauthorized access to system resources, potentially leading to complete system compromise. The vulnerability is particularly dangerous because it can be exploited through web-based XAML applications, making it accessible to attackers without requiring local system access or specialized attack vectors. This makes it a preferred target for remote code execution attacks in environments where .NET Framework applications are prevalent.
The exploitability of CVE-2012-0161 aligns with several tactics described in the MITRE ATT&CK framework, specifically targeting the privilege escalation and execution phases of an attack lifecycle. The vulnerability allows for lateral movement and persistence within compromised environments, as attackers can use the executed code to establish backdoors or further compromise system resources. Organizations running affected .NET Framework versions face significant risk exposure, particularly in web environments where XBAP applications are commonly deployed, as these applications can be delivered through standard web browsers and executed without additional user interaction or privileges. The vulnerability's impact is amplified by the widespread use of .NET Framework across enterprise environments, making it a critical concern for security teams responsible for protecting corporate infrastructure.
Mitigation strategies for this vulnerability require immediate patching of affected .NET Framework versions, as Microsoft released security updates specifically addressing the serialization flaw. Organizations should also implement network segmentation and application whitelisting policies to limit the potential impact of exploitation attempts. Security monitoring should focus on detecting unusual serialization activities and code execution patterns that may indicate exploitation attempts. Additionally, administrators should consider disabling XBAP execution where possible and implementing strict code access security policies to prevent partially trusted code from executing with elevated privileges. The vulnerability serves as a reminder of the critical importance of proper exception handling in security-sensitive code and the need for comprehensive security testing of serialization mechanisms within application frameworks.