CVE-2001-1249 in vWebServer
Summary
by MITRE
vWebServer 1.2.0 allows remote attackers to cause a denial of service via a URL that contains MS-DOS device names.
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Analysis
by VulDB Data Team • 09/27/2025
The vulnerability identified as CVE-2001-1249 affects vWebServer version 1.2.0, a web server implementation that fails to properly handle certain URL requests containing MS-DOS device names. This flaw represents a classic input validation issue that can be exploited to disrupt service availability. The vulnerability stems from the server's inadequate filtering of special characters and device names that are recognized by the MS-DOS operating system, including names such as CON, PRN, AUX, NUL, and COM1 through COM9, as well as LPT1 through LPT9. These device names are reserved in MS-DOS and Windows operating systems and typically cannot be used as filenames in normal file operations.
When a remote attacker crafts a URL containing these device names, the vWebServer processes the request in a manner that causes the server to become unresponsive or crash entirely. This occurs because the server attempts to interpret these special device names as file paths or resources, leading to an abnormal termination of the service or an infinite loop in the processing logic. The exploitation mechanism relies on the server's failure to sanitize input parameters before attempting to resolve or process the requested resource. This vulnerability falls under the category of improper input validation and can be classified as a CWE-20 issue, which specifically addresses improper input sanitization and validation flaws. The attack vector is entirely remote, requiring no authentication or local access, making it particularly dangerous for publicly accessible web servers.
The operational impact of this vulnerability extends beyond simple service disruption, as it can result in complete denial of service for legitimate users attempting to access the web server. The server's inability to properly handle these malformed requests means that any attempt to access a URL containing MS-DOS device names will cause the service to fail, potentially requiring manual intervention to restart the server. This type of vulnerability is particularly concerning in environments where web servers are critical infrastructure components, as it can be exploited to cause significant downtime and potentially impact business operations. The vulnerability also demonstrates poor defensive programming practices and highlights the importance of implementing robust input validation mechanisms. From an attacker's perspective, this represents a low-effort, high-impact method of service disruption that aligns with techniques described in the ATT&CK framework under the service stoppage tactic, where adversaries seek to disable system functionality to achieve their objectives.
The mitigation strategies for CVE-2001-1249 involve implementing comprehensive input validation and sanitization measures within the web server's request processing pipeline. Organizations should ensure that all URL parameters are properly validated against a whitelist of acceptable characters and patterns, specifically excluding MS-DOS device names and other reserved identifiers. The server configuration should include proper error handling and resource management to prevent the exploitation from causing service crashes or resource exhaustion. Additionally, implementing web application firewalls and intrusion prevention systems can help detect and block malicious requests containing these device names. Regular security updates and patches should be applied to ensure that known vulnerabilities are addressed, while also conducting thorough security testing of web applications to identify similar input validation flaws. The vulnerability serves as a reminder of the importance of considering legacy operating system conventions when developing modern web applications and underscores the necessity of robust security controls that can handle unexpected input patterns without compromising system stability.