CVE-2011-1253 in .NET Framework
Summary
by MITRE
Microsoft .NET Framework 1.0 SP3, 1.1 SP1, 2.0 SP2, 3.5.1, and 4, and Silverlight 4 before 4.0.60831, does not properly restrict inheritance, which allows remote attackers to execute arbitrary code via (1) a crafted XAML browser application (aka XBAP), (2) a crafted ASP.NET application, (3) a crafted .NET Framework application, or (4) a crafted Silverlight application, aka ".NET Framework Class Inheritance Vulnerability."
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Analysis
by VulDB Data Team • 11/23/2021
The vulnerability identified as CVE-2011-1253 represents a critical class inheritance flaw within Microsoft .NET Framework versions 1.0 SP3 through 4.0 and Silverlight versions prior to 4.0.60831. This vulnerability stems from insufficient restrictions on inheritance mechanisms within the framework's class hierarchy, creating a pathway for malicious actors to exploit the system through crafted applications. The flaw specifically affects the way the .NET Framework handles class inheritance and object instantiation, allowing attackers to manipulate the inheritance chain to execute unauthorized code. The vulnerability impacts multiple versions of the framework, indicating a widespread issue that affected a significant portion of the software ecosystem during that time period.
The technical exploitation of this vulnerability occurs through four distinct attack vectors that leverage different application types within the .NET ecosystem. Attackers can craft XAML browser applications (XBAPs) that manipulate inheritance chains to execute arbitrary code in the context of the user's session. Similarly, malicious ASP.NET applications can be constructed to exploit the same inheritance flaw, while .NET Framework applications and Silverlight applications can also serve as attack vectors. The core technical issue lies in the improper validation of inheritance relationships, which allows attackers to bypass normal security boundaries and escalate privileges through carefully constructed class hierarchies. This flaw operates at the fundamental level of object-oriented programming within the .NET Framework, where inheritance chains are not properly validated before execution.
The operational impact of this vulnerability is severe and far-reaching, as it enables remote code execution attacks that can compromise entire systems without requiring local access. An attacker who successfully exploits this vulnerability can execute arbitrary code with the privileges of the affected user, potentially leading to complete system compromise, data theft, or further network penetration. The vulnerability's impact extends across multiple deployment scenarios including web applications, desktop applications, and browser-based environments, making it particularly dangerous in enterprise environments where .NET Framework is extensively used. Organizations running affected versions of the framework are at significant risk, as the attack surface includes not only web servers hosting ASP.NET applications but also client machines running XBAP applications or Silverlight plugins. The vulnerability's exploitation does not require special privileges or complex attack chains, making it particularly attractive to threat actors seeking to compromise systems at scale.
Mitigation strategies for CVE-2011-1253 primarily focus on immediate patching of affected systems with the relevant Microsoft security updates. Organizations should prioritize updating all systems running affected versions of the .NET Framework and Silverlight to the latest security patches available from Microsoft. Additionally, network segmentation and application whitelisting can provide temporary protection by limiting the execution of potentially malicious applications. Security administrators should implement monitoring for unusual application behavior and ensure that .NET Framework applications are properly configured with appropriate security settings. The vulnerability aligns with CWE-264, which addresses permissions, privileges, and access controls, and can be mapped to ATT&CK technique T1059.001 for command and scripting interpreter, as attackers may use the vulnerability to execute malicious code through the inherited class mechanisms. Organizations should also review their application deployment practices to ensure that only trusted applications are executed within .NET Framework environments, and implement proper code review processes to identify potential inheritance-related security issues in custom applications.