CVE-2010-3682 in MySQL
Summary
by MITRE
Oracle MySQL 5.1 before 5.1.49 and 5.0 before 5.0.92 allows remote authenticated users to cause a denial of service (mysqld daemon crash) by using EXPLAIN with crafted "SELECT ... UNION ... ORDER BY (SELECT ... WHERE ...)" statements, which triggers a NULL pointer dereference in the Item_singlerow_subselect::store function.
If you want to get the best quality for vulnerability data then you always have to consider VulDB.
Analysis
by VulDB Data Team • 11/01/2024
The vulnerability described in CVE-2010-3682 represents a critical denial of service flaw affecting Oracle MySQL database versions prior to specific patch releases. This issue impacts both MySQL 5.1 versions before 5.1.49 and MySQL 5.0 versions before 5.0.92, creating a significant operational risk for database systems relying on these older versions. The vulnerability stems from improper handling of complex SQL query structures involving explain statements combined with crafted union operations, ultimately leading to daemon crashes that can severely disrupt database services and potentially impact business continuity.
The technical root cause of this vulnerability lies within the Item_singlerow_subselect::store function in MySQL's query processing engine. When an authenticated user submits a specially crafted SQL statement containing EXPLAIN followed by a SELECT statement with UNION and ORDER BY clauses referencing nested subqueries, the system encounters a NULL pointer dereference condition. This occurs during the query execution planning phase where the MySQL daemon attempts to process the complex nested structure. The flaw manifests as a memory access violation when the system tries to dereference a null pointer during the storage operation of subquery results, causing the mysqld daemon to terminate unexpectedly and crash the database service.
The operational impact of this vulnerability extends beyond simple service disruption as it provides attackers with a reliable method to cause persistent database outages. Since the vulnerability requires only authenticated access, it can be exploited by users with legitimate database permissions, making it particularly dangerous in environments where privilege escalation is possible. The crash affects the mysqld daemon process, which means all database connections are severed until the service is manually restarted, potentially causing cascading failures in applications dependent on database connectivity. This vulnerability aligns with CWE-476 which describes NULL pointer dereference conditions, and represents a classic example of how complex query parsing logic can introduce critical stability issues in database systems.
The exploitation of this vulnerability demonstrates a sophisticated understanding of MySQL's internal query execution mechanisms and highlights the importance of proper input validation in database engines. Attackers can craft specific query patterns that trigger memory corruption during the query optimization phase, bypassing typical security controls since the attack requires only legitimate authentication credentials. This makes the vulnerability particularly concerning for production environments where database administrators may not immediately detect unauthorized use of such techniques. Organizations should consider implementing database activity monitoring and anomaly detection systems to identify potential exploitation attempts, as the attack pattern follows predictable behavioral signatures that can be detected through proper log analysis and security information event management systems.
Mitigation strategies for this vulnerability include immediate patching of affected MySQL installations to versions 5.1.49 or later and 5.0.92 or later, which contain the necessary code fixes for proper NULL pointer handling. Additionally, administrators should implement network segmentation to limit database access to trusted sources and consider using database firewalls or query filtering mechanisms to restrict potentially dangerous SQL patterns. The vulnerability also underscores the importance of regular security assessments and vulnerability management programs that can identify and remediate similar issues before they can be exploited in production environments. Organizations should also consider implementing database audit logging to track query execution patterns and identify potential abuse of legitimate database access privileges.