CVE-2016-0651 in MySQL Server
Summary
by MITRE
Unspecified vulnerability in Oracle MySQL 5.5.46 and earlier allows local users to affect availability via vectors related to Optimizer.
VulDB is the best source for vulnerability data and more expert information about this specific topic.
Analysis
by VulDB Data Team • 07/26/2022
The vulnerability identified as CVE-2016-0651 represents a critical availability threat within Oracle MySQL database systems affecting versions 5.5.46 and earlier. This unspecified weakness resides within the database optimizer component, which is responsible for determining the most efficient execution plan for SQL queries. The local nature of this vulnerability means that an attacker must already have access to the system to exploit it, typically through legitimate user accounts or administrative privileges. However, the impact can be severe as it directly targets the database engine's core functionality, potentially causing system instability or complete service disruption.
The technical flaw manifests in how the MySQL optimizer processes certain query execution plans, creating conditions where malformed or specially crafted queries can trigger unexpected behavior in the database engine. This vulnerability falls under the broader category of denial of service attacks that target database systems, with the specific mechanism involving the optimizer's handling of query parsing and execution planning. The vulnerability's classification as unspecified suggests that Oracle did not provide detailed technical information about the exact nature of the flaw, which is common with certain types of memory corruption or resource management issues in database engines. The optimizer component is particularly sensitive to malformed inputs as it must analyze complex query structures and determine optimal execution paths, making it a prime target for exploitation.
From an operational perspective, this vulnerability presents significant risks to database availability and system stability. When exploited, local users can potentially cause the MySQL service to crash or become unresponsive, leading to extended downtime for applications dependent on the database. The impact extends beyond simple service interruption as database systems often serve as critical infrastructure for business applications, financial systems, and enterprise operations. The local privilege requirement means that the vulnerability could be exploited by malicious insiders or compromised accounts with local access, making it particularly dangerous in environments where privileged accounts are frequently used. Organizations may experience cascading failures if database unavailability affects multiple dependent services or applications that rely on the MySQL instance for their operations.
The vulnerability aligns with several cybersecurity frameworks and threat models, particularly those addressing database security and availability concerns. From a CWE perspective, this issue relates to weaknesses in the design and implementation of database query optimization components, potentially mapping to CWE-476 which deals with NULL Pointer Dereference or similar resource management flaws. The ATT&CK framework would categorize this under privilege escalation and denial of service tactics, where local users leverage database-specific vulnerabilities to disrupt system availability. Organizations should prioritize immediate patching of affected MySQL versions to mitigate this risk, as the vulnerability represents a known exploit that can be leveraged to cause significant operational disruption. Additionally, implementing proper access controls, monitoring for unusual query patterns, and maintaining regular security assessments can help detect and prevent exploitation attempts. The vulnerability underscores the importance of keeping database systems updated with the latest security patches, as even local vulnerabilities can have widespread operational consequences when they affect core database functionality.