CVE-2016-3518 in MySQL Server
Summary
by MITRE
Unspecified vulnerability in Oracle MySQL 5.7.12 and earlier allows remote authenticated users to affect availability via vectors related to Server: Optimizer.
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Analysis
by VulDB Data Team • 09/08/2022
The vulnerability identified as CVE-2016-3518 represents a critical availability issue within Oracle MySQL database systems affecting versions 5.7.12 and earlier. This flaw resides within the server's optimizer component, which is responsible for determining the most efficient execution plan for database queries. The unspecified nature of the vulnerability suggests that it may involve multiple attack vectors or conditions that could potentially disrupt database operations. Security researchers have classified this as a remote authenticated vulnerability, meaning that an attacker must possess valid credentials to exploit the flaw, but once exploited, the impact can severely compromise system availability. The optimizer module's role in query execution makes this vulnerability particularly dangerous as it can affect fundamental database operations and potentially cause system crashes or unresponsiveness. This type of vulnerability directly impacts the reliability and uptime of database services, which are critical components in enterprise environments where database availability is paramount for business operations.
The technical implementation of this vulnerability involves the server's optimizer component failing to properly handle certain query execution scenarios, leading to potential denial of service conditions. When authenticated users submit specific queries that trigger the flawed optimizer logic, the system may enter an unstable state that affects its ability to process subsequent requests or maintain normal database operations. The vulnerability's classification under the Server: Optimizer category indicates that the flaw specifically relates to how the MySQL server processes and optimizes database queries rather than issues with authentication, network protocols, or other system components. This places the vulnerability squarely within the realm of database engine internals where optimization algorithms can be manipulated to cause system instability. The impact extends beyond simple query performance degradation to potentially causing complete system unavailability, making it a serious concern for database administrators and security professionals managing MySQL installations.
The operational impact of CVE-2016-3518 can be severe for organizations relying on MySQL database systems, as it directly threatens service availability and can result in significant business disruption. When exploited, this vulnerability can cause database servers to become unresponsive or crash entirely, leading to service outages that affect applications dependent on database operations. The authenticated nature of the attack means that organizations must also consider insider threats or compromised accounts as potential vectors for exploitation, adding another layer of security consideration to their overall risk management strategy. Database administrators may experience difficulties in maintaining service levels and could face challenges in troubleshooting when the vulnerability is exploited, as the symptoms may manifest as general system instability rather than specific error messages. This vulnerability particularly affects environments where database optimization is critical and where multiple concurrent users are performing complex queries that could trigger the flawed optimizer logic. Organizations may need to implement immediate patch management procedures or temporary workarounds to protect against potential exploitation.
Mitigation strategies for CVE-2016-3518 primarily focus on applying the appropriate Oracle security patches and updates that address the optimizer-related vulnerability. Organizations should prioritize upgrading to MySQL versions that have been released after the vulnerability was identified, typically versions 5.7.13 or later, which contain fixes for the specific optimizer flaw. Additionally, implementing network segmentation and access controls can help limit the potential impact of authenticated attacks by restricting which users can access database systems and execute potentially malicious queries. Database administrators should also consider implementing query monitoring and logging mechanisms to detect anomalous query patterns that might indicate exploitation attempts. The vulnerability aligns with CWE-119 which deals with weaknesses in memory management, and potentially CWE-400 which addresses unspecified resource management issues in database systems. From an ATT&CK framework perspective, this vulnerability could be categorized under T1499 which involves resource hijacking or availability compromise, and potentially T1070 which involves indicator removal or system disruption. Organizations should also review their access control policies and ensure that database users have the minimum required privileges to reduce the potential impact of compromised accounts and implement comprehensive monitoring to detect unauthorized access attempts.