CVE-2007-1973 in Windows
Summary
by MITRE
Race condition in the Virtual DOS Machine (VDM) in the Windows Kernel in Microsoft Windows NT 4.0 allows local users to modify memory and gain privileges via the temporary \Device\PhysicalMemory section handle, a related issue to CVE-2007-1206.
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Analysis
by VulDB Data Team • 07/14/2021
The vulnerability described in CVE-2007-1973 represents a critical race condition within the Windows Kernel's Virtual DOS Machine implementation on Windows NT 4.0 systems. This flaw exists in the handling of the temporary \Device\PhysicalMemory section handle, which creates an exploitable window where malicious code can manipulate kernel memory structures. The vulnerability stems from improper synchronization mechanisms during the creation and access of physical memory mappings, allowing local attackers to potentially escalate privileges from user-level to kernel-level execution. The race condition specifically occurs when multiple threads attempt to access the same physical memory section simultaneously, creating opportunities for memory corruption and privilege escalation.
The technical implementation of this vulnerability involves the Windows NT kernel's VDM subsystem which emulates DOS environments for legacy applications. When the system creates temporary handles to physical memory sections, the timing window between handle creation and access allows for manipulation of memory references. This race condition manifests when a malicious process attempts to open the \Device\PhysicalMemory section while another process is in the process of creating or modifying the same memory mapping. The flaw is classified under CWE-362, which specifically addresses race conditions in concurrent programming environments, and aligns with ATT&CK technique T1068 which covers local privilege escalation through kernel vulnerabilities.
The operational impact of this vulnerability extends beyond simple privilege escalation, as it provides attackers with direct access to kernel memory spaces and the ability to modify critical system structures. Local users can leverage this weakness to execute arbitrary code with system-level privileges, potentially leading to complete system compromise. The vulnerability is particularly dangerous in environments where legacy DOS applications are still in use, as the VDM subsystem remains active and accessible. Attackers can exploit this condition to modify system files, inject malicious code into kernel space, or bypass security controls that rely on proper memory protection mechanisms.
Mitigation strategies for CVE-2007-1973 require immediate system updates and configuration hardening measures. Microsoft recommends applying the relevant security patches for Windows NT 4.0, which address the synchronization issues in the VDM subsystem. Organizations should also implement the principle of least privilege by disabling unnecessary VDM functionality and restricting access to physical memory sections. Additional protective measures include monitoring for suspicious handle creation patterns, implementing kernel-mode code integrity checks, and applying runtime protections such as Data Execution Prevention. The vulnerability demonstrates the importance of proper concurrency control in kernel-level code and highlights the risks associated with maintaining legacy subsystems in modern security environments, particularly when these subsystems interact with critical memory management functions.