CVE-2008-7247 in MySQL
Summary
by MITRE
sql/sql_table.cc in MySQL 5.0.x through 5.0.88, 5.1.x through 5.1.41, and 6.0 before 6.0.9-alpha, when the data home directory contains a symlink to a different filesystem, allows remote authenticated users to bypass intended access restrictions by calling CREATE TABLE with a (1) DATA DIRECTORY or (2) INDEX DIRECTORY argument referring to a subdirectory that requires following this symlink.
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Analysis
by VulDB Data Team • 08/28/2021
This vulnerability resides in the MySQL database management system's handling of symbolic links within data directory specifications, specifically affecting versions ranging from 5.0.x through 5.0.88, 5.1.x through 5.1.41, and 6.0 before 6.0.9-alpha. The flaw manifests when the data home directory contains a symbolic link pointing to a different filesystem, creating a path traversal scenario that undermines the intended access controls. The vulnerability is particularly concerning because it allows authenticated remote attackers to bypass access restrictions that should normally prevent unauthorized data access or modification. The technical implementation involves the CREATE TABLE statement with either DATA DIRECTORY or INDEX DIRECTORY arguments that reference subdirectories requiring symlink traversal.
The core technical flaw stems from insufficient validation of symbolic link paths when processing table creation commands. When MySQL processes a CREATE TABLE statement with explicit directory specifications, it fails to properly verify that the target directories are within the intended boundaries. This weakness creates a directory traversal condition where an attacker can manipulate the filesystem path resolution to access areas outside the designated data directories. The vulnerability is categorized under CWE-22 as "Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')" which is a fundamental security flaw in access control mechanisms. This weakness directly enables attackers to circumvent the database's security model by exploiting the symlink resolution process.
The operational impact of this vulnerability extends beyond simple privilege escalation, as it can lead to unauthorized data access, modification, or even data destruction. Attackers can potentially access sensitive data stored in directories that should be restricted, or they might gain write access to areas where they should not have permissions. The vulnerability affects the integrity and confidentiality of the database system, as it allows unauthorized access to data that should remain protected. This issue is particularly dangerous in multi-tenant environments or systems where different users or applications should have isolated data access. The attack requires only authenticated access to the database, making it more exploitable than vulnerabilities requiring additional privileges or conditions.
Mitigation strategies for this vulnerability should focus on both immediate remediation and long-term architectural improvements. The primary solution involves upgrading to patched versions of MySQL where this vulnerability has been addressed through proper symlink validation. Database administrators should implement strict directory permissions and avoid using symbolic links in critical data paths. The recommended approach includes disabling the use of DATA DIRECTORY and INDEX DIRECTORY clauses when creating tables, or implementing strict validation of all directory paths. Organizations should also consider implementing database activity monitoring to detect unusual CREATE TABLE operations with directory specifications. This vulnerability aligns with ATT&CK technique T1078 which covers Valid Accounts and T1566 which covers Phishing, as it exploits legitimate database access to perform unauthorized operations. Additionally, the vulnerability demonstrates the importance of proper input validation and access control implementation in database systems, as highlighted in the OWASP Top 10 2017 category A03: Sensitive Data Exposure.