CVE-2001-1560 in Windows
Summary
by MITRE
Win32k.sys (aka Graphics Device Interface (GDI)) in Windows 2000 and XP allows local users to cause a denial of service (system crash) by calling the ShowWindow function after receiving a WM_NCCREATE message.
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Analysis
by VulDB Data Team • 02/02/2025
The vulnerability described in CVE-2001-1560 resides within the Win32k.sys kernel driver component of Microsoft Windows 2000 and Windows XP operating systems. This driver serves as the core Graphics Device Interface (GDI) implementation responsible for managing graphical user interface elements and system-level graphics operations. The flaw specifically manifests in how the system handles window management messages, particularly the WM_NCCREATE message which is sent during the creation of non-client areas of windows. This represents a classic kernel-mode vulnerability that can be exploited to disrupt system stability through improper message handling.
The technical nature of this vulnerability stems from inadequate input validation within the win32k.sys driver when processing the WM_NCCREATE message in conjunction with the ShowWindow function call. When a local user process attempts to invoke ShowWindow after receiving a WM_NCCREATE message, the kernel driver fails to properly validate the sequence of operations, leading to a memory corruption condition that ultimately results in system instability. This type of vulnerability falls under the CWE-125 vulnerability category, which encompasses out-of-bounds read conditions that can lead to system crashes and denial of service scenarios. The flaw demonstrates poor defensive programming practices in kernel space where proper bounds checking and state validation mechanisms are absent.
The operational impact of this vulnerability is significant as it enables local users to trigger system-wide denial of service conditions without requiring elevated privileges. Since the vulnerability exists within the kernel driver layer, any successful exploitation results in immediate system crash and reboot, effectively rendering the affected system unavailable to legitimate users. This particular weakness is classified under the MITRE ATT&CK technique T1499.004 which describes network denial of service attacks, though in this case the attack vector operates locally within the operating system itself. The vulnerability can be exploited by any user account with local access to the system, making it particularly dangerous in multi-user environments where privilege escalation is not required.
Mitigation strategies for this vulnerability should focus on immediate patch deployment through Microsoft's security updates, as the company released specific fixes for Windows 2000 and XP systems to address the flawed message handling logic in win32k.sys. System administrators should also implement proper access controls and user privilege management to limit local user capabilities, though this does not prevent exploitation since the vulnerability can be triggered by standard user accounts. Network segmentation and monitoring solutions can help detect anomalous behavior patterns that might indicate exploitation attempts. The vulnerability demonstrates the critical importance of kernel-level security testing and proper input validation, as even seemingly benign operations like window management can become attack vectors when proper safeguards are absent. Organizations should also consider implementing additional security measures such as kernel-mode code integrity checking and runtime application control to prevent exploitation of similar vulnerabilities in the future.