CVE-2006-7232 in MySQL
Summary
by MITRE
sql_select.cc in MySQL 5.0.x before 5.0.32 and 5.1.x before 5.1.14 allows remote authenticated users to cause a denial of service (crash) via an EXPLAIN SELECT FROM on the INFORMATION_SCHEMA table, as originally demonstrated using ORDER BY.
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Analysis
by VulDB Data Team • 08/07/2019
This vulnerability exists in MySQL database management systems affecting versions 5.0.x before 5.0.32 and 5.1.x before 5.1.14. The flaw resides in the sql_select.cc source file which handles query execution and result set processing. Attackers with authenticated database access can trigger a denial of service condition by executing specific EXPLAIN SELECT statements against INFORMATION_SCHEMA tables, particularly when ORDER BY clauses are included in the query structure. The vulnerability stems from inadequate input validation and error handling within the query processing pipeline where the system fails to properly manage complex query execution paths involving metadata tables.
The technical implementation of this vulnerability exploits the interaction between the EXPLAIN command and INFORMATION_SCHEMA table access. When an authenticated user executes an EXPLAIN SELECT statement that includes an ORDER BY clause on INFORMATION_SCHEMA tables, the MySQL query optimizer encounters a condition that causes memory corruption or invalid pointer dereference within the sql_select.cc module. This occurs because the system does not properly validate the complexity of query execution paths when dealing with metadata queries that involve ordering operations. The vulnerability is classified under CWE-121 as a buffer overflow condition, though it manifests as a denial of service rather than arbitrary code execution. The attack requires only authenticated access to the database system, making it particularly concerning for environments where database users have elevated privileges.
The operational impact of this vulnerability extends beyond simple service disruption as it can affect database availability and potentially compromise the integrity of database operations. When the MySQL server crashes due to this vulnerability, it requires manual intervention to restart the database service, leading to potential downtime for applications dependent on that database. This type of denial of service attack can be particularly damaging in production environments where database availability is critical for business operations. The vulnerability also demonstrates a weakness in the database's query processing architecture, where metadata table access is not properly isolated from complex query execution paths that could lead to system instability. Organizations using affected MySQL versions may experience unexpected service interruptions during routine database administration tasks.
Mitigation strategies for this vulnerability should include immediate patching of affected MySQL installations to versions 5.0.32 or 5.1.14 and later. Database administrators should also implement monitoring solutions to detect unusual query patterns that might indicate exploitation attempts, particularly focusing on EXPLAIN statements against INFORMATION_SCHEMA tables. Access controls should be strengthened to limit database user privileges and reduce the attack surface where authenticated users can execute potentially malicious queries. Additionally, implementing query timeouts and resource limits can help prevent exploitation attempts from causing prolonged system instability. The vulnerability highlights the importance of proper input validation in database query processing systems and aligns with ATT&CK technique T1499.004 for denial of service attacks. Organizations should also consider implementing database activity monitoring to detect and alert on suspicious query patterns that could indicate attempts to exploit this or similar vulnerabilities in database systems.