CVE-2000-0838 in FUR HTTP Server
Summary
by MITRE
Fastream FUR HTTP server 1.0b allows remote attackers to cause a denial of service via a long GET request.
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Analysis
by VulDB Data Team • 04/06/2019
The Fastream FUR HTTP server version 1.0b contains a critical vulnerability that enables remote attackers to execute denial of service attacks through carefully crafted long GET requests. This vulnerability represents a classic buffer overflow condition where the server fails to properly validate the length of incoming HTTP GET requests, leading to potential system instability and service disruption. The flaw exists in the server's request parsing mechanism, specifically within how it handles the URL portion of HTTP GET requests, making it susceptible to malformed input that exceeds allocated buffer boundaries.
This vulnerability falls under the broader category of buffer overflow conditions classified as CWE-121, which encompasses unsafe buffer access patterns that can lead to memory corruption and system instability. The attack vector specifically targets the HTTP server's inability to handle oversized request parameters, creating a scenario where an attacker can send a GET request containing an excessive number of characters in the URL portion, causing the server process to crash or become unresponsive. The vulnerability demonstrates poor input validation practices and inadequate boundary checking mechanisms that are fundamental requirements for secure network service implementations.
The operational impact of this vulnerability extends beyond simple service disruption to potentially compromise the entire server availability. When exploited, the denial of service condition can render the HTTP server completely inaccessible to legitimate users, affecting web applications hosted on the server and potentially impacting business operations. The vulnerability affects the server's ability to process legitimate requests while simultaneously being vulnerable to malicious exploitation, creating a scenario where system administrators must either restart the service or implement temporary workarounds to restore functionality. This type of attack aligns with the ATT&CK technique T1498, which describes network denial of service attacks that target the availability of services and systems.
Mitigation strategies for this vulnerability should include immediate patching of the Fastream FUR HTTP server to version 1.0b or later, which contains the necessary fixes for buffer handling and input validation. Network administrators should implement rate limiting and request length restrictions at the firewall or proxy level to prevent excessively long requests from reaching the vulnerable server. Additionally, monitoring systems should be configured to detect unusual patterns of long GET requests that may indicate attempted exploitation. The vulnerability also highlights the importance of implementing proper security testing practices including fuzzing and input validation testing to identify similar buffer overflow conditions in other network services. Organizations should consider implementing intrusion detection systems that can identify and block suspicious HTTP request patterns, particularly those containing unusually long URL parameters that exceed typical web application requirements.