CVE-2000-0168 in Internet Explorer
Summary
by MITRE
Microsoft Windows 9x operating systems allow an attacker to cause a denial of service via a pathname that includes file device names, aka the "DOS Device in Path Name" vulnerability.
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Analysis
by VulDB Data Team • 02/23/2025
The CVE-2000-0168 vulnerability represents a critical denial of service flaw affecting Microsoft Windows 9x operating systems that stems from improper handling of device names within file pathnames. This vulnerability exploits the fundamental way these legacy operating systems process file paths containing device identifiers such as CON, PRN, AUX, NUL, and COM1 through COM9, as well as LPT1 through LPT9. The flaw exists because the Windows 9x kernel fails to properly validate and sanitize pathname components that include these reserved device names, creating a condition where maliciously crafted file paths can trigger system instability.
The technical implementation of this vulnerability involves the operating system's file system driver attempting to resolve pathnames that contain device names as part of the file path structure. When the system encounters a pathname such as "C:\CON\file.txt" or "C:\PRN\test.dat", the kernel's path resolution mechanism becomes confused and enters a state where it cannot properly handle the file operations. This occurs because the Windows 9x operating system treats device names as special entities that should not appear within regular file paths, yet the validation mechanism fails to properly intercept and reject these malformed paths before they reach the core file system routines.
The operational impact of this vulnerability extends beyond simple system crashes, as it can be exploited by attackers to create persistent denial of service conditions that may require system reboot to resolve. Attackers can leverage this vulnerability by constructing file paths that include device names, causing applications and system services to fail when attempting to access or manipulate these paths. The vulnerability affects the core file system functionality and can be triggered through various means including web browsing, email attachments, or network file sharing operations. The system behavior manifests as application crashes, system freezes, or complete system hangs that prevent normal operation until manual intervention occurs.
This vulnerability aligns with CWE-120, which addresses buffer overflow conditions in software, and demonstrates the importance of proper input validation in operating system components. From an attacker perspective, this vulnerability maps to ATT&CK technique T1499.004, which covers network denial of service attacks, and represents a classic example of how improper input sanitization can lead to system instability. The flaw specifically impacts the Windows 9x family including Windows 95, Windows 98, and Windows ME, which were widely deployed in enterprise and consumer environments during the late 1990s and early 2000s. Security researchers have documented that exploitation of this vulnerability can be achieved through simple path manipulation without requiring elevated privileges, making it particularly dangerous in multi-user environments where untrusted users might be able to influence file path resolution.
Mitigation strategies for CVE-2000-0168 primarily involve applying the security patches released by Microsoft as part of their regular update cycle, though many organizations running legacy Windows 9x systems may have limited ability to upgrade due to compatibility concerns. System administrators should implement network segmentation and access controls to limit user exposure to potentially malicious file paths, while also monitoring for unusual file access patterns that might indicate exploitation attempts. The vulnerability highlights the importance of proper path validation in operating system kernel components and serves as a reminder of the risks associated with legacy operating system support in enterprise environments. Organizations should consider migrating away from unsupported Windows 9x platforms to modern operating systems that have robust input validation mechanisms and are regularly updated with security patches.