CVE-2014-0237 in Mac OS X
Summary
by MITRE • 01/25/2023
The cdf_unpack_summary_info function in cdf.c in the Fileinfo component in PHP before 5.4.29 and 5.5.x before 5.5.13 allows remote attackers to cause a denial of service (performance degradation) by triggering many file_printf calls.
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Analysis
by VulDB Data Team • 01/25/2023
The vulnerability identified as CVE-2014-0237 resides within the Fileinfo component of PHP, specifically in the cdf_unpack_summary_info function located in cdf.c. This flaw represents a performance degradation issue that can be exploited remotely to cause denial of service conditions. The vulnerability affects PHP versions prior to 5.4.29 and 5.5.x versions before 5.5.13, making it a significant concern for systems running these outdated versions. The issue stems from the function's handling of compound document file format (CDF) structures, which are commonly used in Microsoft Office documents and other applications that utilize this file format.
The technical exploitation of this vulnerability occurs when an attacker crafts a malicious file that triggers excessive file_printf calls within the cdf_unpack_summary_info function. This function is responsible for unpacking summary information from compound document files, and under normal circumstances would process these structures efficiently. However, the flaw allows an attacker to manipulate the input data in such a way that the function repeatedly invokes file_printf operations, leading to significant performance degradation. This behavior can be characterized as a resource exhaustion attack where the system's processing capabilities are consumed unnecessarily, ultimately resulting in denial of service conditions.
From an operational perspective, this vulnerability poses substantial risks to web applications and servers that utilize PHP's Fileinfo extension for file type detection or content analysis. When exploited, the vulnerability can cause servers to become unresponsive or significantly slow down processing of legitimate requests, effectively creating a denial of service condition. The impact extends beyond simple service disruption as it can affect multiple concurrent requests and potentially lead to complete system unavailability. Attackers can leverage this vulnerability without requiring authentication or special privileges, making it particularly dangerous for publicly accessible web applications. The performance degradation occurs during the file analysis phase, which means that even legitimate file uploads or processing operations could be affected by the attacker's malicious input.
The vulnerability aligns with CWE-400, which classifies it as a resource exhaustion issue, specifically involving excessive resource consumption through algorithmic complexity or excessive processing operations. This categorization reflects the fundamental nature of the flaw where the system's processing resources are consumed in an abnormal manner. From an attacker's perspective, this vulnerability maps to several ATT&CK techniques including T1499.004 for network denial of service and T1059.007 for command and scripting interpreter. The attack chain typically involves an initial reconnaissance phase where the attacker identifies vulnerable systems, followed by the delivery of malicious files that trigger the specific code path within the cdf_unpack_summary_info function, ultimately leading to performance degradation.
Mitigation strategies for this vulnerability primarily involve upgrading to patched versions of PHP where the issue has been resolved. Organizations should prioritize updating their PHP installations to versions 5.4.29 or later for the 5.4.x branch, and 5.5.13 or later for the 5.5.x branch. Additionally, implementing proper input validation and sanitization measures can help reduce the risk of exploitation, although the most effective solution remains the application of the vendor-provided security patches. Network-level protections such as rate limiting and file type restrictions can provide additional layers of defense, though they cannot fully prevent exploitation of this specific vulnerability. Security monitoring should include detection of unusual processing patterns or resource consumption spikes that may indicate exploitation attempts. The vulnerability also highlights the importance of keeping all software components up to date and maintaining comprehensive patch management processes to prevent similar issues from affecting systems in the future.