CVE-2002-1823 in Zeroo HTTP Server
Summary
by MITRE
Buffer overflow in the HttpGetRequest function in Zeroo HTTP server 1.5 allows remote attackers to execute arbitrary code via a long HTTP request.
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Analysis
by VulDB Data Team • 09/01/2025
The vulnerability identified as CVE-2002-1823 represents a critical buffer overflow flaw within the Zeroo HTTP server version 1.5 implementation. This issue specifically affects the HttpGetRequest function which processes incoming HTTP requests from remote clients. The flaw arises from inadequate input validation and bounds checking mechanisms within the server's request handling code, creating a scenario where maliciously crafted HTTP requests can trigger memory corruption. The vulnerability classifies under CWE-121 as a stack-based buffer overflow, where an attacker can overwrite adjacent memory locations including return addresses and function pointers. This type of vulnerability is particularly dangerous because it allows for arbitrary code execution, making it a prime target for exploitation in network-based attacks. The Zeroo HTTP server 1.5 was widely deployed in enterprise environments and small-scale web serving applications, amplifying the potential impact of this vulnerability across numerous systems.
The technical exploitation of this buffer overflow occurs when a remote attacker sends an HTTP request containing an excessively long payload that exceeds the allocated buffer size within the HttpGetRequest function. When the server attempts to process this oversized request, the lack of proper boundary checking causes data to overflow into adjacent memory regions. This overflow can overwrite the stack frame's return address, allowing an attacker to redirect execution flow to malicious code injected within the request payload. The vulnerability is particularly concerning because it requires no authentication or privileged access to exploit, making it a remote code execution vulnerability that can be leveraged by anyone capable of sending HTTP requests to the affected server. The specific nature of the overflow in the HTTP request processing pipeline means that the attack surface includes all HTTP methods that utilize this particular function, potentially affecting GET, POST, and other request types depending on the server's configuration.
The operational impact of CVE-2002-1823 extends far beyond simple service disruption, as successful exploitation can lead to complete system compromise and unauthorized access to sensitive data. Attackers who successfully exploit this vulnerability can gain full control over the affected server, potentially using it as a launch point for further attacks within the network infrastructure. The vulnerability affects systems running Zeroo HTTP server 1.5, which was commonly deployed in small business environments, web hosting services, and embedded systems where security updates may not have been regularly applied. Organizations using this server version were particularly vulnerable as the software was not receiving regular security patches, and the buffer overflow could be exploited through various attack vectors including web browsing, automated scanning tools, or direct HTTP request manipulation. The long-term implications include potential data breaches, system infiltration, and the establishment of persistent backdoors within affected networks.
Mitigation strategies for CVE-2002-1823 should prioritize immediate software updates and patches provided by the vendor, as the Zeroo HTTP server 1.5 was discontinued and no longer receives security updates. Organizations should implement network segmentation and access controls to limit exposure to this vulnerability, particularly by blocking unnecessary HTTP traffic to affected servers. The implementation of intrusion detection systems can help identify potential exploitation attempts through monitoring for unusually long HTTP requests or malformed payloads. Additionally, network administrators should consider deploying web application firewalls that can filter out suspicious HTTP request patterns and provide an additional layer of protection. The vulnerability also highlights the importance of proper input validation and bounds checking in all server-side applications, aligning with ATT&CK technique T1203 which covers exploitation of software vulnerabilities. Organizations should conduct comprehensive vulnerability assessments to identify all systems running affected software versions and ensure that legacy HTTP servers are either patched, updated, or removed from production environments to prevent potential exploitation.