CVE-2007-4889 in PHP
Summary
by MITRE
The MySQL extension in PHP 5.2.4 and earlier allows remote attackers to bypass safe_mode and open_basedir restrictions via the MySQL (1) LOAD_FILE, (2) INTO DUMPFILE, and (3) INTO OUTFILE functions, a different issue than CVE-2007-3997.
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Analysis
by VulDB Data Team • 07/21/2021
The vulnerability identified as CVE-2007-4889 represents a critical security flaw in PHP versions 5.2.4 and earlier that specifically affects the MySQL extension. This vulnerability enables remote attackers to circumvent fundamental security restrictions that are designed to limit file access and system interactions within PHP applications. The issue manifests through three distinct MySQL functions that are commonly used for data import and export operations, creating multiple attack vectors that can be exploited by malicious actors to gain unauthorized access to system resources.
The technical flaw resides in how PHP's MySQL extension handles file operations when executing the LOAD_FILE, INTO DUMPFILE, and INTO OUTFILE SQL commands. These functions are typically restricted by PHP's safe_mode and open_basedir directives to prevent unauthorized file system access, but the vulnerability allows attackers to bypass these protections entirely. The flaw stems from insufficient validation and sanitization of file paths and operations within the MySQL extension, enabling attackers to specify arbitrary file locations that would normally be restricted. This bypass occurs because the extension does not properly enforce the security boundaries established by PHP's configuration settings, allowing file operations to proceed outside the intended scope of the web application's access permissions.
The operational impact of this vulnerability is severe and far-reaching for any system running affected PHP versions. Attackers can leverage this flaw to read arbitrary files from the target system, potentially accessing sensitive configuration files, database credentials, application source code, or other confidential data that should remain protected. The ability to write files using INTO DUMPFILE and INTO OUTFILE functions creates additional risks including the potential for code injection, backdoor installation, or system compromise through the creation of malicious files in writable directories. This vulnerability essentially provides attackers with a pathway to escalate privileges and gain deeper access to the underlying system infrastructure, making it particularly dangerous for web applications that handle sensitive data or operate in regulated environments where compliance requirements are paramount.
Security professionals should implement immediate mitigations including upgrading to PHP versions 5.2.5 or later where this vulnerability has been addressed through proper enforcement of safe_mode and open_basedir restrictions. Organizations should also review their current PHP configurations to ensure that safe_mode is properly enabled and that open_basedir restrictions are correctly implemented to limit file system access. Additional defensive measures include implementing network-level restrictions to limit access to MySQL servers, monitoring database operations for suspicious file access patterns, and conducting regular security assessments of web applications to identify potential exploitation vectors. The vulnerability aligns with CWE-22, which describes improper limitation of a pathname to a restricted directory, and represents a specific implementation flaw that violates the principle of least privilege in system security design. From an ATT&CK framework perspective, this vulnerability maps to T1059.006 for execution through web shell commands and T1566 for initial access through vulnerable web applications, making it a critical target for both prevention and detection efforts in enterprise security programs.