CVE-2001-0649 in Personal Web Sharing
Summary
by MITRE
Personal Web Sharing 1.5.5 allows a remote attacker to cause a denial of service via a long HTTP request.
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Analysis
by VulDB Data Team • 12/26/2024
The vulnerability identified as CVE-2001-0649 affects Personal Web Sharing version 1.5.5, a web server component that was part of Microsoft's Windows 2000 operating system. This flaw represents a classic buffer overflow condition that occurs when the web server processes malformed HTTP requests. The vulnerability stems from insufficient input validation within the HTTP request handling mechanism, where the server fails to properly sanitize or limit the length of incoming request data. When a remote attacker crafts an HTTP request containing an excessive number of characters, the server's buffer allocation becomes exhausted, leading to a system crash or complete service disruption. The flaw specifically impacts the server's ability to process HTTP headers and request lines, making it susceptible to exploitation through carefully constructed malicious requests.
The technical implementation of this vulnerability aligns with CWE-121, which describes stack-based buffer overflow conditions, and CWE-122, which addresses heap-based buffer overflow scenarios. The attack vector operates through the network layer where remote adversaries can send specially crafted HTTP requests to the vulnerable server without requiring authentication or prior access. The exploitation process involves sending an HTTP request containing an abnormally long string in the request line or headers, which causes the server process to exceed its allocated memory buffer space. This results in memory corruption that ultimately leads to process termination or system instability. The vulnerability demonstrates poor input validation practices and inadequate error handling within the web server's request processing pipeline, creating a scenario where malformed input can directly translate into system compromise.
The operational impact of this vulnerability extends beyond simple service disruption to potentially enable more sophisticated attacks within a compromised network environment. When the denial of service occurs, legitimate users lose access to the web services hosted on the vulnerable system, which can have significant business implications for organizations relying on these services. The vulnerability affects the availability aspect of the CIA triad, as it prevents authorized users from accessing legitimate web content. Attackers can leverage this vulnerability to perform service disruption attacks that may serve as a precursor to more advanced exploitation techniques or simply to create chaos within target networks. The lack of authentication requirements for exploitation makes this particularly dangerous as it can be executed by anyone with network access to the vulnerable system, potentially allowing for large-scale disruption attacks against multiple targets.
Mitigation strategies for CVE-2001-0649 should focus on immediate patching and configuration hardening measures. Microsoft released security updates that addressed this vulnerability through proper input validation and buffer size restrictions within the web server component. Organizations should implement network segmentation and access controls to limit exposure to this vulnerability, particularly in environments where the Personal Web Sharing component remains active. Network monitoring solutions should be configured to detect anomalous HTTP request patterns that may indicate exploitation attempts, including unusually long request lines or header values. The implementation of web application firewalls can provide additional protection by filtering malformed HTTP requests before they reach the vulnerable server. System administrators should also consider disabling unnecessary web services and implementing proper network access controls to reduce the attack surface. From an ATT&CK perspective, this vulnerability relates to T1499.004, which covers network denial of service, and T1566.002, which addresses spearphishing through social engineering, as attackers may use this vulnerability as part of broader attack campaigns. Regular security assessments and vulnerability scanning should be conducted to identify and remediate similar issues in other web server components and applications within the network infrastructure.