CVE-2012-2386 in PHP
Summary
by MITRE
Integer overflow in the phar_parse_tarfile function in tar.c in the phar extension in PHP before 5.3.14 and 5.4.x before 5.4.4 allows remote attackers to cause a denial of service (application crash) or possibly execute arbitrary code via a crafted tar file that triggers a heap-based buffer overflow.
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Analysis
by VulDB Data Team • 11/24/2024
The vulnerability identified as CVE-2012-2386 represents a critical integer overflow flaw within the phar extension of PHP, specifically affecting the phar_parse_tarfile function in tar.c. This vulnerability exists in PHP versions prior to 5.3.14 and 5.4.x before 5.4.4, creating a significant security risk for web applications that utilize PHP's phar extension for handling archive files. The flaw stems from improper handling of integer values during tar file parsing operations, which can lead to unpredictable behavior when processing maliciously crafted archive files.
The technical implementation of this vulnerability involves the manipulation of integer arithmetic within the phar extension's tar file processing logic. When a malicious tar file is processed, the phar_parse_tarfile function fails to properly validate integer values, causing an integer overflow condition that subsequently triggers a heap-based buffer overflow. This occurs because the function does not adequately check the size parameters of archive entries before allocating memory buffers, allowing attackers to craft tar files with oversized or malformed size fields that exceed the intended buffer boundaries. The vulnerability falls under CWE-190, which specifically addresses integer overflow conditions, and aligns with ATT&CK technique T1203 for exploitation of memory corruption vulnerabilities.
The operational impact of this vulnerability extends beyond simple denial of service to potentially enabling remote code execution, making it particularly dangerous for web applications. When exploited, the heap-based buffer overflow can cause application crashes, leading to denial of service conditions that disrupt legitimate user access. However, the more severe implications arise from the potential for arbitrary code execution, which could allow attackers to gain unauthorized access to affected systems. The vulnerability affects PHP applications that process user-supplied tar files through the phar extension, making it relevant to content management systems, file upload functionalities, and any web application that utilizes PHP's archive handling capabilities. Attackers can leverage this flaw by uploading or providing malicious tar files that, when processed by the vulnerable PHP application, trigger the integer overflow and subsequent buffer overflow conditions.
Mitigation strategies for CVE-2012-2386 primarily focus on immediate patching of affected PHP installations to versions 5.3.14 or 5.4.4 and later. Organizations should prioritize updating their PHP environments and thoroughly test patches to ensure compatibility with existing applications. Additional defensive measures include implementing strict input validation for all file uploads, particularly those involving archive formats, and configuring web applications to sanitize and verify file metadata before processing. Network-level controls such as web application firewalls can provide additional protection by filtering suspicious file content patterns, though these should complement rather than replace proper software updates. The vulnerability demonstrates the critical importance of proper integer handling and memory management in security-sensitive applications, emphasizing the need for regular security audits and vulnerability assessments to identify similar flaws in application code and third-party libraries.