CVE-2002-2401 in Windows
Summary
by MITRE
NT Virtual DOS Machine (NTVDM.EXE) in Windows 2000, NT and XP does not verify user execution permissions for 16-bit executable files, which allows local users to bypass the loader and execute arbitrary programs.
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Analysis
by VulDB Data Team • 01/21/2025
The vulnerability described in CVE-2002-2401 resides within the NT Virtual DOS Machine component of Microsoft Windows operating systems including Windows 2000, Windows NT, and Windows XP. This flaw represents a critical security weakness in the system's privilege execution model where the NTVDM.EXE process fails to properly validate user permissions when loading 16-bit executable files. The issue stems from the legacy support mechanisms designed to maintain compatibility with older 16-bit applications while running on 32-bit Windows architectures.
The technical flaw manifests as a missing permission check within the loader mechanism of NTVDM.EXE that handles 16-bit application execution. When a user attempts to execute a 16-bit program through the virtual DOS machine, the system should verify that the executing user has appropriate permissions to run the target executable. However, due to the vulnerability, this verification process is bypassed entirely, allowing any local user to execute arbitrary programs with the privileges of the current user context. This represents a direct violation of the principle of least privilege and creates a pathway for privilege escalation attacks.
The operational impact of this vulnerability extends beyond simple unauthorized execution, as it enables attackers to circumvent standard security controls that would normally prevent execution of malicious code. Local users can exploit this weakness to run unauthorized programs without proper authentication or authorization, potentially leading to system compromise through the execution of malware, backdoors, or other malicious payloads. The vulnerability is particularly concerning because it operates at the system level within the Windows kernel execution environment, making it difficult to detect and prevent through conventional security measures.
This vulnerability aligns with CWE-284, which describes improper access control mechanisms, and represents a classic case of privilege escalation through improper permission validation. From an attack framework perspective, this issue maps to ATT&CK technique T1068, which covers local privilege escalation through the exploitation of system vulnerabilities. The attack surface is broad since any local user with access to the system can potentially exploit this weakness, making it particularly dangerous in multi-user environments where users may have varying privilege levels.
Mitigation strategies should focus on immediate patching of affected systems through Microsoft security updates, as well as implementing additional security controls such as restricted user accounts, enhanced file system permissions, and monitoring for unauthorized executable activity. Organizations should also consider disabling NTVDM.EXE functionality entirely if 16-bit application compatibility is not required, and implement network segmentation to limit potential lateral movement if exploitation occurs. Regular security audits should verify that the vulnerability has been properly addressed and that no residual attack vectors remain available to malicious actors.