CVE-2014-9426 in PHP
Summary
by MITRE
** DISPUTED ** The apprentice_load function in libmagic/apprentice.c in the Fileinfo component in PHP through 5.6.4 attempts to perform a free operation on a stack-based character array, which allows remote attackers to cause a denial of service (memory corruption or application crash) or possibly have unspecified other impact via unknown vectors. NOTE: this is disputed by the vendor because the standard erealloc behavior makes the free operation unreachable.
Be aware that VulDB is the high quality source for vulnerability data.
Analysis
by VulDB Data Team • 10/29/2024
The vulnerability identified as CVE-2014-9426 resides within the Fileinfo component of PHP versions through 5.6.4, specifically within the apprentice_load function located in libmagic/apprentice.c. This issue represents a potential memory management flaw that could be exploited by remote attackers to disrupt application functionality or potentially achieve more severe consequences. The vulnerability is classified as disputed by the vendor due to the standard erealloc behavior making the free operation unreachable, yet it remains significant for understanding memory corruption risks in file type detection libraries.
The technical flaw manifests in the apprentice_load function where an attempt is made to perform a free operation on a stack-based character array. This memory management error occurs during the processing of file type detection operations, particularly when handling magic file parsing through the Fileinfo extension. The stack-based character array represents a memory allocation that should not be subject to explicit deallocation operations, yet the code attempts to free it, creating a potential memory corruption scenario that could lead to application instability or crashes.
From an operational perspective, this vulnerability presents a denial of service risk to PHP applications that rely on the Fileinfo extension for file type detection. Attackers could potentially craft malicious file inputs or magic files that trigger the problematic code path, causing the application to crash or behave unpredictably. The unspecified other impacts mentioned in the description suggest that while the primary concern is denial of service, there may be additional security implications that could be exploited under certain conditions. The vulnerability affects the core file type detection functionality that many web applications depend upon for security validation and file handling.
The impact of this vulnerability extends beyond simple service disruption as it represents a memory corruption issue that could potentially be leveraged for more sophisticated attacks if exploitation vectors are identified. The use of stack-based arrays in conjunction with free operations creates a dangerous pattern that violates standard memory management practices. This flaw aligns with common weakness enumerations such as CWE-415 which describes double free conditions, though the specific implementation details here involve stack-based memory management rather than heap-based operations. The vulnerability demonstrates the importance of proper memory management in security-critical components and highlights the need for thorough code review of file parsing and type detection libraries.
Mitigation strategies for this vulnerability should focus on upgrading to PHP versions where the issue has been resolved, as the vendor has disputed the vulnerability due to the unreachable free operation. However, administrators should still consider implementing proper input validation and sanitization for file type detection operations. The recommended approach involves maintaining updated PHP installations, implementing proper file validation mechanisms, and monitoring for any potential exploitation attempts. Organizations should also consider implementing network-level protections and application firewalls to limit exposure to potential attackers who might attempt to exploit related vulnerabilities in file handling components. The disputed nature of this vulnerability underscores the importance of vendor communication and proper vulnerability assessment in security management practices.