CVE-2003-1558 in fnord
Summary
by MITRE
Buffer overflow in httpd.c of fnord 1.6 allows remote attackers to create a denial of service (crash) and possibly execute arbitrary code via a long CGI request passed to the do_cgi function.
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Analysis
by VulDB Data Team • 06/17/2018
The vulnerability identified as CVE-2003-1558 represents a critical buffer overflow flaw within the fnord web server version 1.6, specifically affecting the httpd.c component. This vulnerability resides in the handling of CGI requests within the do_cgi function, creating a pathway for remote attackers to exploit the system through malformed input. The flaw stems from inadequate input validation and bounds checking mechanisms that fail to properly sanitize the length of CGI parameters passed to the server. When an attacker submits a specially crafted request containing an excessively long CGI parameter, the server processes this input without proper boundary enforcement, leading to memory corruption that can trigger program termination or potentially allow code execution. The vulnerability operates at the application layer and affects the web server's ability to process legitimate requests while simultaneously creating opportunities for malicious actors to disrupt service availability or gain unauthorized access to the system.
The technical implementation of this buffer overflow vulnerability aligns with CWE-121, which describes stack-based buffer overflow conditions where insufficient bounds checking allows attackers to overwrite adjacent memory locations. The flaw manifests when the do_cgi function processes CGI input parameters without validating their length against predetermined buffer sizes, creating an exploitable condition that can be leveraged through network-based attacks. This vulnerability directly impacts the integrity and availability of the web server service, as demonstrated by the potential for both denial of service and arbitrary code execution scenarios. The attack vector requires network access to the vulnerable web server and can be executed without authentication, making it particularly dangerous in publicly accessible environments. The buffer overflow occurs during the processing of CGI requests, which are commonly used for dynamic content generation and user interaction within web applications, amplifying the potential impact of the vulnerability across various web-based services.
The operational impact of CVE-2003-1558 extends beyond simple service disruption to encompass potential system compromise and data integrity violations. A successful exploitation can result in immediate denial of service conditions where the web server crashes and becomes unavailable to legitimate users, while also potentially enabling attackers to execute arbitrary code with the privileges of the web server process. This compromise can lead to unauthorized access to sensitive data, privilege escalation opportunities, and further lateral movement within the network infrastructure. The vulnerability affects organizations relying on fnord 1.6 web server implementations, particularly those hosting dynamic web applications that utilize CGI scripts for user interaction. From an ATT&CK framework perspective, this vulnerability maps to T1499.004 (Network Denial of Service) and potentially T1059.007 (Command and Scripting Interpreter: Unix Shell) when exploitation leads to code execution, demonstrating the multi-faceted nature of the threat. The vulnerability's exploitation requires minimal technical expertise and can be automated, making it attractive to both novice and advanced attackers seeking to disrupt services or establish persistent access to target systems.
Mitigation strategies for CVE-2003-1558 should prioritize immediate patching of the fnord web server to version 1.6.1 or later, which contains the necessary buffer overflow protections and input validation improvements. Organizations should implement network-based restrictions such as firewall rules that limit access to CGI endpoints and monitor for unusual request patterns that might indicate exploitation attempts. Input validation should be enhanced at multiple layers including web server configuration, application-level filters, and network intrusion detection systems. Regular security assessments and vulnerability scanning should be conducted to identify similar buffer overflow conditions in other web server implementations and application code. Additionally, implementing proper logging and monitoring of web server activities can help detect exploitation attempts and provide forensic evidence for incident response activities. The vulnerability serves as a reminder of the critical importance of proper input validation and bounds checking in preventing buffer overflow exploits, emphasizing the need for secure coding practices and regular security updates to maintain robust defenses against evolving threats.