CVE-2015-8865 in PHP
Prediction
by VulDB Data Team • 05/12/2025
A flaw has been found in PHP up to 5.5.33/5.6.19/5.22/7.0.4. Affected by this issue is the function file_check_mem of the file funcs.c of the component Continuation-Level Jump Handler. Executing a manipulation can lead to buffer overflow. It is possible to launch the attack remotely. Upgrading to version 5.5.34, 5.6.20, 5.23 and 7.0.5 can resolve this issue. Upgrading the affected component is recommended.
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Analysis
by VulDB Data Team • 05/12/2025
The vulnerability identified as CVE-2015-8865 represents a critical flaw in PHP's Fileinfo component that affects multiple versions of the PHP runtime environment. This issue resides within the file_check_mem function located in the funcs.c file, which is responsible for processing magic files used by the fileinfo extension to determine file types. The flaw manifests when the function improperly handles continuation-level jumps during magic file processing, creating a condition where maliciously crafted magic files can trigger unexpected behavior in the application. This vulnerability falls under the CWE-121 category of Stack-based Buffer Overflow, specifically involving improper handling of memory operations during file type detection processes.
The technical exploitation of this vulnerability occurs when an attacker crafts a malicious magic file that contains specially constructed continuation-level jumps that cause the file_check_mem function to miscalculate memory allocation or buffer boundaries. When PHP's Fileinfo extension processes this crafted file, the improper handling of these jumps leads to buffer overflows that can result in application crashes or potentially allow remote code execution. The vulnerability is context-dependent, meaning that successful exploitation requires the target system to process a specifically crafted magic file through the fileinfo extension, typically during file type detection operations. The attack vector is particularly concerning because it can be triggered through standard file type detection mechanisms, making it accessible to attackers who can influence file processing operations.
From an operational perspective, this vulnerability poses significant risks to web applications that rely on PHP's fileinfo extension for file type validation or content detection. The potential impact includes complete service disruption through denial of service conditions, where applications crash and become unavailable to legitimate users. More critically, the possibility of arbitrary code execution means that attackers could potentially gain control over affected systems, leading to data breaches, system compromise, or further lateral movement within network environments. The vulnerability affects all PHP versions prior to the specified patched releases, making it particularly widespread across legacy systems that may not have been updated. Organizations using PHP-based web applications, content management systems, or file upload validation mechanisms are particularly at risk.
Mitigation strategies for CVE-2015-8865 primarily focus on immediate patching of affected PHP installations to versions that contain the necessary fixes for the file_check_mem function. System administrators should prioritize updating their PHP environments to PHP 5.5.34, 5.6.20, or 7.0.5, depending on their current version. Additionally, organizations should implement proper input validation and sanitization for any file processing operations, particularly those involving user-uploaded files. Network-level defenses can include monitoring for suspicious file type detection patterns and implementing web application firewalls that can detect and block malicious magic file patterns. The ATT&CK framework categorizes this vulnerability under the T1059.007 technique for command and scripting interpreter, as successful exploitation could lead to code execution capabilities. Organizations should also consider implementing least privilege principles for file processing operations and regularly audit their PHP configurations to ensure that the fileinfo extension is not being used inappropriately or exposed to untrusted inputs.