CVE-2008-5658 in PHP
Summary
by MITRE
Directory traversal vulnerability in the ZipArchive::extractTo function in PHP 5.2.6 and earlier allows context-dependent attackers to write arbitrary files via a ZIP file with a file whose name contains .. (dot dot) sequences.
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Analysis
by VulDB Data Team • 08/22/2019
The vulnerability identified as CVE-2008-5658 represents a critical directory traversal flaw within PHP's ZipArchive::extractTo function affecting versions 5.2.6 and earlier. This security weakness stems from inadequate input validation and path sanitization mechanisms within the ZIP file extraction process, creating a pathway for malicious actors to manipulate file paths during decompression operations. The vulnerability specifically exploits the handling of .. (dot dot) sequences in filenames contained within ZIP archives, allowing attackers to specify arbitrary file paths that can bypass normal extraction boundaries and write files to locations outside the intended target directory.
The technical exploitation of this vulnerability occurs when a PHP application utilizes the ZipArchive::extractTo function to decompress user-supplied ZIP files without proper validation of the archive contents. When a malicious ZIP file contains filenames with .. sequences, the extraction process fails to properly sanitize these paths, enabling attackers to craft archive entries that, when extracted, will overwrite files in arbitrary locations on the filesystem. This flaw operates at the file system level where the .. sequences are interpreted as parent directory references, allowing the attacker to traverse up the directory hierarchy and potentially write to sensitive system locations. The vulnerability is context-dependent as it requires a PHP application to be processing untrusted ZIP archives through the vulnerable ZipArchive::extractTo method, making it particularly dangerous in web applications that handle file uploads or provide archive extraction functionality.
The operational impact of CVE-2008-5658 extends beyond simple file overwrites to potentially enable complete system compromise through various attack vectors. An attacker could leverage this vulnerability to overwrite critical system files, web application configuration files, or even execute arbitrary code by targeting PHP files that are subsequently processed by the web server. This vulnerability directly maps to CWE-22 - Improper Limitation of a Pathname to a Restricted Directory, which is classified under the Common Weakness Enumeration framework as a fundamental path traversal weakness. The attack pattern aligns with techniques described in the MITRE ATT&CK framework under T1059 - Command and Scripting Interpreter and T1078 - Valid Accounts, as it enables attackers to modify system components and potentially establish persistence through file manipulation. The vulnerability's severity is amplified in environments where PHP applications process untrusted user input, particularly in web applications that allow file upload functionality or provide archive extraction services, making it a prime target for exploitation in web application attacks.
Mitigation strategies for CVE-2008-5658 primarily focus on immediate version upgrades to PHP 5.2.7 or later, where the vulnerability has been addressed through improved input validation and path sanitization within the ZipArchive::extractTo function. Organizations should implement comprehensive input validation measures that sanitize all filenames extracted from ZIP archives, rejecting any paths containing .. sequences or other potentially malicious path components. Additionally, applications should restrict the extraction directory to predefined safe locations and implement proper access controls to limit the impact of potential exploitation. Network-level defenses such as web application firewalls and intrusion detection systems can provide additional layers of protection by monitoring for suspicious file extraction patterns. The remediation process should include thorough code reviews to identify all instances where ZipArchive::extractTo is used, ensuring that proper validation and sanitization measures are implemented. Organizations should also establish secure coding practices that emphasize the importance of validating all external inputs and implementing least privilege principles when processing archive files. Regular security assessments and vulnerability scanning should be conducted to identify similar path traversal vulnerabilities in other components of the application stack, as this type of weakness often indicates broader security gaps in input handling and validation processes.