CVE-2008-4098 in MySQL
Summary
by MITRE
MySQL before 5.0.67 allows local users to bypass certain privilege checks by calling CREATE TABLE on a MyISAM table with modified (1) DATA DIRECTORY or (2) INDEX DIRECTORY arguments that are originally associated with pathnames without symlinks, and that can point to tables created at a future time at which a pathname is modified to contain a symlink to a subdirectory of the MySQL home data directory. NOTE: this vulnerability exists because of an incomplete fix for CVE-2008-4097.
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Analysis
by VulDB Data Team • 08/20/2019
This vulnerability in MySQL versions prior to 5.0.67 represents a sophisticated privilege escalation issue that exploits weaknesses in the database system's directory handling mechanisms. The flaw specifically affects the CREATE TABLE statement functionality when dealing with MyISAM tables, creating a pathway for local attackers to circumvent intended security controls. The vulnerability stems from insufficient validation of directory paths during table creation operations, allowing malicious actors to manipulate file system references through carefully crafted symlink attacks. This issue demonstrates the complexity of privilege management in database systems and highlights how seemingly minor implementation gaps can lead to significant security breaches.
The technical exploitation occurs through the manipulation of DATA DIRECTORY and INDEX DIRECTORY parameters within CREATE TABLE statements. When these parameters reference paths that initially lack symbolic links, attackers can modify the target directory structure at a later time to include symlinks pointing to sensitive MySQL data subdirectories. This creates a race condition where the privilege check is performed against the original non-symlinked path, but the actual table creation occurs when the symlink has been established, allowing access to restricted areas. The vulnerability specifically targets the path resolution process during table creation, where the system fails to properly validate directory paths against the current file system state rather than the state at the time of the privilege check.
The operational impact of this vulnerability extends beyond simple privilege escalation to potentially enable complete system compromise when combined with other attack vectors. Local attackers can leverage this flaw to create tables in directories where they would normally lack write permissions, potentially leading to data manipulation, information disclosure, or even the installation of malicious components within the database environment. The vulnerability's persistence lies in its ability to exploit temporal inconsistencies in path validation, making detection difficult and the attack surface broad. This type of vulnerability directly relates to CWE-22 Path Traversal and CWE-78 Improper Neutralization of Special Elements used in OS Commands, as it combines path manipulation with privilege escalation techniques.
The vulnerability's existence as an incomplete fix for CVE-2008-4097 demonstrates the complexity of security patching and the potential for remediation gaps in software security. Organizations running affected MySQL versions face significant risk as this vulnerability allows local users to bypass critical access controls that protect database integrity and confidentiality. The attack requires local system access but can be particularly damaging in multi-tenant environments where database users may have varying privilege levels. This flaw aligns with ATT&CK technique T1068, which covers local privilege escalation through exploitation of software vulnerabilities, and T1566, which covers social engineering tactics that might be used to gain initial access.
Mitigation strategies should focus on immediate patching to MySQL version 5.0.67 or later, which contains the proper fix for this vulnerability. System administrators should also implement strict file system permissions and monitoring for unauthorized symlink creation in MySQL data directories. Additional protective measures include restricting local user access to database systems, implementing file integrity monitoring solutions, and conducting regular security assessments of database configurations. Organizations should also consider implementing database activity monitoring to detect anomalous CREATE TABLE operations that might indicate exploitation attempts. The vulnerability serves as a reminder of the importance of comprehensive security testing, particularly for privilege management systems, and the need for thorough validation of security patches to ensure complete remediation of identified issues.