CVE-2009-2497 in .NET Framework
Summary
by MITRE
The Common Language Runtime (CLR) in Microsoft .NET Framework 2.0, 2.0 SP1, 2.0 SP2, 3.5, and 3.5 SP1, and Silverlight 2, does not properly handle interfaces, which allows remote attackers to execute arbitrary code via (1) a crafted XAML browser application (XBAP), (2) a crafted Silverlight application, (3) a crafted ASP.NET application, or (4) a crafted .NET Framework application, aka "Microsoft Silverlight and Microsoft .NET Framework CLR Vulnerability."
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Analysis
by VulDB Data Team • 08/23/2021
The vulnerability described in CVE-2009-2497 represents a critical security flaw within the Common Language Runtime component of Microsoft's .NET Framework ecosystem. This issue affects multiple versions including .NET Framework 2.0 through 3.5 SP1 and Silverlight 2, creating a wide attack surface that spans across different application types and deployment scenarios. The vulnerability stems from improper handling of interfaces within the CLR, which serves as the foundational execution environment for managed code applications. This flaw specifically impacts how the runtime processes interface contracts during application execution, creating potential entry points for malicious code injection.
The technical exploitation of this vulnerability occurs through four distinct attack vectors that leverage different application types within the Microsoft ecosystem. Attackers can craft malicious XAML browser applications (XBAPs) that, when executed in a browser context, trigger the interface handling flaw in the CLR. Similarly, malicious Silverlight applications can be designed to exploit the same vulnerability during execution within the Silverlight runtime environment. ASP.NET applications can also be compromised by crafting malicious code that leverages the interface handling weakness, while .NET Framework applications can be targeted through direct manipulation of interface contracts. These attack methods demonstrate the breadth of the vulnerability's impact across different application deployment models and execution contexts.
The operational impact of this vulnerability is severe as it allows remote attackers to execute arbitrary code on affected systems without requiring local privileges. This means that an attacker could potentially compromise a user's system simply by convincing them to view a maliciously crafted application or webpage. The vulnerability's reach extends beyond individual applications to potentially affect entire enterprise environments where .NET Framework applications are deployed. System administrators face significant challenges in mitigating this issue since it affects multiple versions and application types, requiring careful coordination across different deployment scenarios. The potential for privilege escalation exists through the execution of arbitrary code, which could lead to complete system compromise depending on the execution context and user privileges.
Mitigation strategies for CVE-2009-2497 should focus on immediate patch application through Microsoft's security updates, which address the underlying interface handling flaw in the CLR. Organizations should implement network segmentation and application whitelisting policies to limit the execution of potentially malicious applications, particularly those related to XBAPs and Silverlight applications. Security monitoring should be enhanced to detect suspicious execution patterns and unauthorized application installations. The vulnerability aligns with CWE-119 which addresses improper restriction of operations within a limited context, and relates to ATT&CK technique T1059 which covers command and scripting interpreter. System administrators should also consider disabling Silverlight and XBAP execution in browser environments where these technologies are not essential for business operations. Regular security assessments and vulnerability scanning should be conducted to identify and remediate any remaining instances of affected software versions across the enterprise infrastructure.