CVE-2007-3997 in PHP
Summary
by MITRE
The (1) MySQL and (2) MySQLi extensions in PHP 4 before 4.4.8, and PHP 5 before 5.2.4, allow remote attackers to bypass safe_mode and open_basedir restrictions via MySQL LOCAL INFILE operations, as demonstrated by a query with LOAD DATA LOCAL INFILE.
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Analysis
by VulDB Data Team • 10/07/2024
The vulnerability described in CVE-2007-3997 represents a critical security flaw in PHP's MySQL and MySQLi extensions that affects versions prior to 4.4.8 and 5.2.4 respectively. This issue stems from improper handling of MySQL LOCAL INFILE operations within the PHP runtime environment, creating a pathway for remote attackers to circumvent fundamental security restrictions that are designed to limit file system access. The vulnerability specifically targets the safe_mode and open_basedir directives that are standard PHP security mechanisms intended to prevent unauthorized file access and directory traversal attacks.
The technical exploitation of this vulnerability occurs through the LOAD DATA LOCAL INFILE SQL command which allows MySQL to read data from local files on the server. When PHP processes MySQL queries containing this command, the underlying MySQL client library can be manipulated to bypass PHP's security controls. This happens because the PHP extensions do not properly validate or restrict the file paths that can be accessed through the LOCAL INFILE functionality, allowing attackers to specify arbitrary file locations that would normally be restricted by safe_mode and open_basedir settings. The flaw exists at the interface level between PHP and the MySQL client library, where input validation is insufficient to prevent malicious file path manipulation.
The operational impact of this vulnerability is severe as it allows attackers to access files that should be protected by PHP's security mechanisms, potentially leading to data breaches, privilege escalation, and system compromise. An attacker could leverage this vulnerability to read sensitive files such as configuration files, password databases, or other system files that are typically protected by the open_basedir restriction. The ability to bypass safe_mode means that attackers can access files outside of the designated document root and restricted directories, effectively nullifying the security boundaries that PHP provides. This vulnerability is particularly dangerous in shared hosting environments where multiple users operate under the same PHP instance and security restrictions are crucial for maintaining isolation between different applications and users.
This vulnerability aligns with CWE-22, which describes improper limitation of a pathname to a restricted directory, and CWE-254, which covers security features that are not properly implemented. The attack pattern follows the techniques described in MITRE ATT&CK framework under T1059 for command and scripting interpreter and T1078 for valid accounts, as attackers can use this vulnerability to gain unauthorized access to system resources. The remediation strategy involves updating PHP installations to versions 4.4.8 or 5.2.4 and later, where the MySQL and MySQLi extensions properly validate file paths during LOCAL INFILE operations. Additionally, administrators should disable the LOCAL INFILE functionality in MySQL configuration when it is not required, and implement proper input validation at the application level to prevent malicious SQL injection attacks that could exploit this vulnerability. The fix addresses the root cause by ensuring that PHP properly enforces the security restrictions that are fundamental to preventing unauthorized file system access.