CVE-2000-0643 in WEBactive
Summary
by MITRE
Buffer overflow in WebActive HTTP Server 1.00 allows remote attackers to cause a denial of service via a long URL.
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Analysis
by VulDB Data Team • 10/13/2025
The vulnerability identified as CVE-2000-0643 represents a critical buffer overflow flaw within the WebActive HTTP Server version 1.00 that exposes the system to remote exploitation. This type of vulnerability falls under the common weakness enumeration category CWE-121, which specifically addresses stack-based buffer overflow conditions where insufficient bounds checking allows attackers to overwrite adjacent memory locations. The flaw manifests when the server processes HTTP requests containing excessively long URLs that exceed the allocated buffer space, creating an opportunity for malicious actors to manipulate the server's memory structure.
The technical implementation of this vulnerability occurs at the application layer where the WebActive HTTP Server fails to properly validate the length of incoming URL parameters during request processing. When a remote attacker submits a malformed HTTP request with an abnormally long URL, the server's internal buffer handling mechanism cannot accommodate the excessive input data, resulting in memory corruption that can lead to unpredictable behavior including application crashes or complete system downtime. This particular implementation demonstrates a classic stack buffer overflow pattern where the overflow occurs in a function that processes URL strings without adequate input length validation.
The operational impact of this vulnerability extends beyond simple denial of service conditions, as it creates potential pathways for more sophisticated attacks that could compromise the entire server infrastructure. The remote nature of the exploit means that attackers do not require physical access or local privileges to trigger the vulnerability, making it particularly dangerous in production environments where the server handles critical web traffic. Systems running this vulnerable version of WebActive HTTP Server become susceptible to persistent disruption attacks that can be executed from anywhere on the internet, potentially causing significant business interruption and loss of service availability for legitimate users.
Organizations should implement immediate mitigations including applying the latest security patches provided by the vendor, implementing input validation controls at the network perimeter through firewalls and web application firewalls, and conducting thorough vulnerability assessments to identify any other potentially affected systems. The ATT&CK framework categorizes this vulnerability under the technique T1499.004 for Network Denial of Service, highlighting the importance of implementing robust input sanitization measures and monitoring for unusual traffic patterns that might indicate exploitation attempts. Additionally, system administrators should consider deploying intrusion detection systems that can identify and block malformed HTTP requests containing excessively long URL parameters, thereby reducing the attack surface and preventing successful exploitation of this buffer overflow vulnerability.