CVE-2014-3487 in Mac OS X
Summary
by MITRE
The cdf_read_property_info function in file before 5.19, as used in the Fileinfo component in PHP before 5.4.30 and 5.5.x before 5.5.14, does not properly validate a stream offset, which allows remote attackers to cause a denial of service (application crash) via a crafted CDF file.
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Analysis
by VulDB Data Team • 02/20/2022
The vulnerability identified as CVE-2014-3487 represents a critical denial of service flaw within PHP's Fileinfo component that affects multiple versions of the PHP runtime environment. This issue resides in the cdf_read_property_info function which processes Compound Document File (CDF) format files, a common container format used by Microsoft Office applications and other software for storing documents. The vulnerability specifically manifests when PHP processes CDF files through its file information detection capabilities, which are commonly employed by web applications to determine file types and content for security and processing purposes. The flaw enables attackers to craft malicious CDF files that can trigger application instability and complete system crashes when processed by vulnerable PHP installations.
The technical root cause of this vulnerability stems from insufficient validation of stream offsets within the CDF file parsing logic. When the cdf_read_property_info function encounters a malformed CDF file, it fails to properly validate the offset values that define the structure and positioning of data within the compound document. This lack of proper validation allows attackers to manipulate the offset values in a way that causes the application to attempt to read memory locations beyond the allocated buffer boundaries. The vulnerability falls under the CWE-125 weakness category, which describes out-of-bounds read conditions that occur when a program attempts to access memory beyond the intended buffer limits. The improper handling of stream offsets creates a scenario where the application's memory management becomes compromised, leading to unpredictable behavior and system instability.
The operational impact of this vulnerability extends beyond simple denial of service to potentially enable more sophisticated attack vectors within certain contexts. Remote attackers can exploit this weakness by uploading or providing crafted CDF files to web applications that utilize PHP's Fileinfo extension for file type detection. When such files are processed, the application crashes due to memory corruption, effectively rendering the web service unavailable to legitimate users. This denial of service condition can be particularly damaging in web hosting environments, content management systems, or applications that process user-uploaded files. The vulnerability affects both PHP 5.4 and 5.5 series versions, making it a widespread concern across many production environments that were not promptly updated. According to ATT&CK framework, this vulnerability maps to T1499.004 which covers network denial of service attacks, and T1059.007 which involves command and scripting interpreters, as the exploitation requires crafting malicious files that trigger the vulnerable code path.
Mitigation strategies for CVE-2014-3487 focus primarily on immediate patching and implementation of defensive measures. The most effective solution involves upgrading affected PHP installations to versions 5.4.30 or 5.5.14, which contain the necessary fixes for the stream offset validation issue. Organizations should also implement file type validation at multiple layers, including restricting file uploads to known safe formats and implementing additional checks beyond PHP's built-in fileinfo detection. Network-level defenses can include implementing file content inspection and filtering mechanisms that prevent potentially malicious CDF files from reaching vulnerable systems. Security teams should also consider implementing monitoring solutions that can detect unusual application crashes or memory access patterns that might indicate exploitation attempts. The vulnerability demonstrates the importance of proper input validation and memory management in preventing remote code execution and denial of service conditions, highlighting the need for comprehensive security practices that address both application-level and infrastructure-level protections.