CVE-2016-0658 in MySQL Server
Summary
by MITRE
Unspecified vulnerability in Oracle MySQL 5.7.10 and earlier allows local users to affect availability via vectors related to Optimizer.
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Analysis
by VulDB Data Team • 07/26/2022
The vulnerability identified as CVE-2016-0658 represents a significant security weakness within Oracle MySQL database systems affecting versions 5.7.10 and earlier. This issue resides within the optimizer component of the database engine, which is responsible for determining the most efficient execution plan for SQL queries. The unspecified nature of the vulnerability indicates that the exact technical mechanism remains undisclosed, though it is classified as a local privilege escalation vector that can compromise system availability. Such vulnerabilities are particularly concerning because they can be exploited by attackers with local access to the system, potentially leading to denial of service conditions that disrupt database operations and compromise data accessibility. The impact extends beyond simple availability issues as database unavailability can cascade into broader system failures affecting applications dependent on the database infrastructure.
The technical flaw manifests within the MySQL optimizer module, which processes and optimizes SQL statements before execution. This component is critical to database performance as it determines how queries should be executed to minimize resource consumption and maximize efficiency. When the optimizer encounters certain malformed or specially crafted queries, it can fail in ways that lead to system instability or complete service disruption. The vulnerability is categorized as a local attack vector, meaning that exploitation requires an attacker to already have access to the system with local user privileges, typically through legitimate user accounts or compromised system access. This classification aligns with CWE-20, which describes improper input validation as a common weakness that can lead to various security issues including availability disruption. The attack surface is particularly narrow since it requires local system access, but the potential impact on database availability makes it a critical concern for system administrators.
The operational impact of this vulnerability can be severe for organizations relying on MySQL databases, as it directly affects the availability of database services and can result in significant downtime. When exploited, the vulnerability can cause the MySQL service to crash or become unresponsive, preventing legitimate database operations from proceeding normally. This disruption can cascade through application systems that depend on database connectivity, potentially causing business interruption and data access failures. The vulnerability affects the overall reliability of database infrastructure and can compromise the integrity of database operations, particularly in environments where high availability and consistent database performance are critical requirements. Organizations may experience service degradation or complete outages, leading to potential data loss or corruption, depending on how long the database remains unavailable. The impact is further amplified in mission-critical systems where database unavailability can result in substantial financial losses and operational disruption.
Mitigation strategies for CVE-2016-0658 primarily focus on immediate patching and system hardening measures. Organizations should prioritize updating to MySQL versions that have addressed this vulnerability, typically those released after the initial patching cycle for this specific issue. System administrators should implement strict access controls and privilege management to limit local system access, thereby reducing the attack surface for potential exploitation. Monitoring and logging mechanisms should be enhanced to detect unusual database behavior or service disruptions that could indicate exploitation attempts. Additionally, implementing network segmentation and access controls can help prevent unauthorized local access to database systems. The vulnerability's classification as a local privilege escalation issue emphasizes the importance of maintaining secure system access controls and user privilege management. Organizations should also consider implementing database activity monitoring solutions that can detect anomalous query patterns or service disruptions that might indicate exploitation attempts. Regular security assessments and vulnerability scanning should be conducted to identify potential exposure to similar vulnerabilities and ensure comprehensive protection against both current and emerging threats.
This vulnerability demonstrates the critical importance of maintaining up-to-date database software and implementing comprehensive security measures. The fact that it affects the optimizer component highlights the need for thorough testing and validation of database components, particularly those involved in query processing and execution. The local access requirement does not diminish the severity of the issue, as local privilege escalation vulnerabilities can often be leveraged as stepping stones for more extensive attacks. Organizations should maintain robust patch management processes and ensure that database systems are regularly updated with security patches. The vulnerability also underscores the importance of following security best practices such as least privilege access, regular system monitoring, and incident response planning to effectively manage and mitigate the risks associated with database security vulnerabilities.