CVE-2015-1673 in .NET Framework
Summary
by MITRE
The Windows Forms (aka WinForms) libraries in Microsoft .NET Framework 1.1 SP1, 2.0 SP2, 3.5, 3.5.1, 4, 4.5, 4.5.1, and 4.5.2 allow user-assisted remote attackers to execute arbitrary code via a crafted partial-trust application, aka "Windows Forms Elevation of Privilege Vulnerability."
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Analysis
by VulDB Data Team • 05/17/2022
The Windows Forms Elevation of Privilege Vulnerability identified as CVE-2015-1673 represents a critical security flaw within Microsoft .NET Framework versions spanning from 1.1 Service Pack 1 through 4.5.2. This vulnerability specifically affects the Windows Forms libraries that handle graphical user interface components in .NET applications. The flaw exists in how the framework processes partial-trust applications, which are designed to run with limited permissions in restricted security contexts. Attackers can exploit this weakness by crafting malicious partial-trust applications that appear legitimate to the security system but contain code designed to escalate privileges beyond their intended restrictions. The vulnerability operates under the Common Weakness Enumeration CWE-264, which categorizes it as a permissions and access control weakness, specifically related to inadequate privilege management within application frameworks.
The technical exploitation of this vulnerability occurs through a sophisticated manipulation of the .NET security model's trust boundaries. When a malicious application runs in partial-trust mode, the system should restrict its capabilities to prevent unauthorized access to system resources. However, the flaw allows attackers to bypass these security restrictions by leveraging specific methods within the Windows Forms libraries that should normally be protected from execution in restricted contexts. The vulnerability essentially enables a privilege escalation attack where an application running with limited permissions can execute code with elevated privileges, potentially gaining access to sensitive system resources, files, and processes. This occurs because the security checks that should prevent such escalation are either insufficient or can be circumvented through careful crafting of the malicious application's code structure and method calls.
The operational impact of this vulnerability is severe and far-reaching across enterprise environments that utilize affected .NET Framework versions. Organizations running applications that depend on Windows Forms components are at risk of complete system compromise when attackers successfully exploit this flaw. The vulnerability can be triggered remotely through user-assisted attack vectors, meaning that an attacker does not necessarily need to have direct access to the target system but can entice users to execute the malicious application. This makes the attack surface particularly broad since it can be delivered through various channels including email attachments, web downloads, or malicious websites. The potential consequences include unauthorized data access, system takeover, privilege escalation to administrator level, and the ability to install malicious software or modify system configurations without proper authorization.
Mitigation strategies for CVE-2015-1673 focus primarily on applying Microsoft security patches and updates as recommended through the Microsoft Security Response Center. Organizations should immediately deploy the relevant security updates for their specific .NET Framework versions, as Microsoft released comprehensive patches addressing this vulnerability. Additionally, administrators should implement network segmentation and access controls to limit the potential impact of exploitation, particularly by restricting the execution of partial-trust applications in critical environments. Security monitoring should be enhanced to detect unusual privilege escalation activities or unexpected execution of applications with elevated permissions. The vulnerability aligns with ATT&CK technique T1068, which describes privilege escalation through the exploitation of application vulnerabilities, and organizations should consider implementing application whitelisting policies to prevent execution of untrusted applications. System hardening practices including disabling unnecessary .NET Framework features and implementing strict code access security policies can further reduce the risk of exploitation. Regular security assessments and vulnerability scanning should be conducted to identify systems running unsupported .NET Framework versions that may be vulnerable to this and related exploitation techniques.