CVE-2005-1793 in Windows
Summary
by MITRE
User32.DLL in Microsoft Windows 98SE, and possibly other operating systems, allows local and remote attackers to cause a denial of service (crash) via an icon (.ico) bitmap file with large width and height values.
If you want to get the best quality for vulnerability data then you always have to consider VulDB.
Analysis
by VulDB Data Team • 05/03/2019
The vulnerability described in CVE-2005-1793 represents a classic buffer overflow condition affecting the User32.DLL component within Microsoft Windows 98 Second Edition and potentially other operating systems. This issue stems from inadequate input validation when processing icon bitmap files with excessively large width and height parameters. The vulnerability resides in the Windows graphical subsystem where icon files are loaded and processed, making it accessible to both local and remote attackers who can exploit the flaw through maliciously crafted icon files. The affected User32.DLL module handles user interface elements including icons, cursors, and window management functions, creating a critical attack surface for denial of service exploits. This vulnerability specifically targets the icon loading mechanism that occurs when Windows processes .ico files, which are commonly used for application icons, system notifications, and graphical user interface elements across the operating system.
The technical flaw manifests when the system attempts to allocate memory for processing icon bitmap files containing oversized width and height values that exceed the expected parameter ranges. The underlying cause can be categorized as a classic integer overflow or improper bounds checking issue where the system fails to validate the dimensions of icon files before attempting to process them. When an attacker supplies an icon file with deliberately large width and height values, the system's memory allocation routines attempt to create buffers based on these exaggerated parameters, resulting in either memory corruption or excessive memory consumption that ultimately leads to system instability. This type of vulnerability typically maps to CWE-129, which covers insufficient validation of length of input buffers, and may also align with CWE-190, dealing with integer overflow or wraparound conditions. The vulnerability operates at the kernel level within the Windows graphical subsystem, making it particularly dangerous as it can compromise the stability of the entire operating system interface.
The operational impact of this vulnerability extends beyond simple system crashes, as it can be leveraged to create persistent denial of service conditions that affect user productivity and system availability. Local attackers can exploit this vulnerability by placing malicious icon files in locations accessible to the Windows shell or application execution paths, while remote attackers can potentially deliver the exploit through web-based icon loading scenarios or file sharing protocols. The vulnerability's potential for remote exploitation makes it particularly concerning in networked environments where users might encounter malicious icon files through email attachments, web downloads, or shared network resources. Systems running Windows 98 SE are especially vulnerable due to the age of the operating system and the lack of modern input validation mechanisms that would prevent such exploits. The impact can range from individual application crashes to complete system hangs or reboots, depending on how deeply the icon loading process integrates with system stability.
Mitigation strategies for this vulnerability should focus on immediate patching and system hardening measures. Microsoft released patches for this vulnerability as part of their regular security updates, and organizations should ensure all affected systems receive these updates promptly. System administrators should implement strict file validation policies for icon files, particularly those received from untrusted sources, and consider disabling automatic icon loading for potentially malicious file types. Network segmentation and access controls can help limit the potential impact of remote exploitation attempts by restricting access to systems that might be vulnerable. The use of application whitelisting and restricted user privileges can prevent local attackers from successfully exploiting this vulnerability by limiting their ability to place malicious files in system directories. Additionally, implementing network monitoring solutions that can detect unusual icon file processing patterns or memory allocation spikes may provide early warning of exploitation attempts. This vulnerability serves as a reminder of the importance of robust input validation in graphical user interface components and highlights the need for continuous security assessment of legacy operating systems that may not receive ongoing security updates. The ATT&CK framework would categorize this vulnerability under T1499 for network denial of service and T1059 for command and scripting interpreter, as attackers might use this vulnerability as a stepping stone for further exploitation attempts.