CVE-2023-3824 in Communications Diameter Signaling Router
Summary
by MITRE • 08/11/2023
In PHP version 8.0.* before 8.0.30, 8.1.* before 8.1.22, and 8.2.* before 8.2.8, when loading phar file, while reading PHAR directory entries, insufficient length checking may lead to a stack buffer overflow, leading potentially to memory corruption or RCE.
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Analysis
by VulDB Data Team • 12/13/2024
The vulnerability identified as CVE-2023-3824 represents a critical stack buffer overflow flaw within PHP's handling of phar files, affecting multiple versions including 8.0.x before 8.0.30, 8.1.x before 8.1.22, and 8.2.x before 8.2.8. This issue resides in the phar extension's directory entry parsing mechanism where inadequate length validation allows maliciously crafted phar archives to trigger memory corruption during file processing. The vulnerability stems from insufficient bounds checking when reading directory entries from phar files, creating an exploitable condition that can be leveraged by attackers to execute arbitrary code on affected systems.
The technical implementation of this vulnerability occurs within PHP's phar extension when it processes directory entries from phar archives. During the parsing of directory structures, the code fails to properly validate the length of data fields before copying them into fixed-size stack buffers. This allows an attacker to craft a phar file containing malformed directory entry data that exceeds the allocated buffer space, resulting in stack corruption. The flaw specifically manifests when PHP attempts to load and process phar files that contain specially constructed directory entries with oversized metadata fields. This condition falls under the CWE-121 stack-based buffer overflow category, which is classified as a critical vulnerability in the Common Weakness Enumeration catalog.
The operational impact of CVE-2023-3824 extends beyond simple memory corruption, as it can potentially enable remote code execution on systems running vulnerable PHP versions. Attackers can exploit this vulnerability by uploading or delivering malicious phar files to systems where PHP processes user-supplied phar content, such as web applications that accept phar file uploads or applications that automatically process phar archives. The vulnerability is particularly dangerous in web environments where phar files might be processed without proper validation, as it can be triggered through standard file upload mechanisms or when applications include phar files from untrusted sources. This makes the vulnerability highly relevant to the ATT&CK framework's initial access and execution tactics, particularly under the T1190 and T1059 categories where adversaries leverage software vulnerabilities to gain system access.
Mitigation strategies for this vulnerability require immediate patching of affected PHP installations to versions that address the buffer overflow condition. Organizations should prioritize updating their PHP environments to the latest stable releases that include fixes for this specific flaw. Additionally, administrators should implement strict input validation for phar file processing, disable phar extension usage where possible, and employ proper file upload restrictions to prevent malicious phar files from being processed. Security measures should include monitoring for suspicious phar file activity and implementing network-based detection mechanisms that can identify potentially malicious phar file patterns. The vulnerability demonstrates the importance of proper bounds checking in memory management and highlights the critical need for regular security updates in web application environments where PHP is utilized for file processing operations.