CVE-2012-2329 in PHP
Summary
by MITRE
Buffer overflow in the apache_request_headers function in sapi/cgi/cgi_main.c in PHP 5.4.x before 5.4.3 allows remote attackers to cause a denial of service (application crash) via a long string in the header of an HTTP request.
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Analysis
by VulDB Data Team • 09/08/2025
The vulnerability identified as CVE-2012-2329 represents a critical buffer overflow flaw within the PHP web server interface component that affects versions 5.4.x prior to 5.4.3. This issue resides in the apache_request_headers function located within the sapi/cgi/cgi_main.c file, which serves as the core interface between PHP and the Apache web server when using the CGI interface. The flaw manifests when processing HTTP request headers, specifically when handling unusually long string values in the header fields. The vulnerability operates at the application layer and represents a classic buffer overflow condition that can be exploited through carefully crafted HTTP requests containing oversized header data. This type of vulnerability falls under the CWE-121 buffer overflow category, which is classified as a fundamental memory safety issue in software development practices. The attack vector is particularly concerning because it can be executed remotely without requiring authentication or special privileges, making it accessible to any attacker capable of sending HTTP requests to the affected PHP application.
The technical exploitation of this vulnerability occurs when the apache_request_headers function attempts to process HTTP headers that exceed the allocated buffer space within the PHP CGI interface. The function fails to properly validate or limit the length of header strings before copying them into fixed-size memory buffers, creating an exploitable condition where an attacker can overflow the buffer and potentially overwrite adjacent memory locations. This memory corruption can lead to unpredictable application behavior, including segmentation faults, application crashes, and ultimately complete denial of service for the affected web server instance. The vulnerability is particularly dangerous in web server environments where PHP applications handle untrusted input from external clients, as the overflow can occur during normal HTTP request processing without requiring any special attack conditions or user interaction. The impact extends beyond simple service disruption, as the memory corruption can potentially be leveraged to execute arbitrary code or escalate privileges depending on the system configuration and memory layout.
The operational impact of CVE-2012-2329 presents significant risks for organizations running vulnerable PHP applications, particularly those using the CGI interface with Apache web servers. A successful exploitation can result in complete service outages, requiring system administrators to restart web server processes and potentially causing extended downtime for affected applications. The vulnerability affects the availability aspect of the CIA triad, specifically targeting denial of service conditions that can be triggered through simple HTTP request manipulation. Organizations relying on PHP-based web applications in production environments face substantial risk of service interruption, which can translate into financial losses, reputation damage, and potential compliance violations. The vulnerability's remote exploitability means that attackers can target systems from anywhere on the internet without requiring physical access or network proximity, making it particularly attractive for automated exploitation campaigns. This type of vulnerability is often categorized under the MITRE ATT&CK framework as a denial of service attack technique, specifically targeting application availability through memory corruption methods.
Mitigation strategies for CVE-2012-2329 primarily focus on immediate software updates and system hardening measures. The most effective solution involves upgrading to PHP version 5.4.3 or later, which contains the necessary patches to address the buffer overflow condition in the apache_request_headers function. System administrators should also implement input validation measures at the web server level, such as configuring maximum header size limits in Apache configuration files using directives like LimitRequestFieldSize and LimitRequestLine. Network-level protections can include implementing rate limiting and connection throttling mechanisms to prevent abuse of the vulnerability through automated attack tools. Additionally, organizations should consider deploying web application firewalls that can detect and block suspicious header patterns that may indicate exploitation attempts. Security monitoring should include logging and alerting for unusual HTTP request patterns, particularly those with unusually long header values. The vulnerability highlights the importance of proper input validation and memory management in web application development, aligning with industry best practices for secure coding and the OWASP Top Ten security risks. Regular security assessments and vulnerability scanning should be conducted to identify and remediate similar issues in other components of the web application stack, as buffer overflow vulnerabilities often indicate broader security weaknesses in software development practices.