CVE-2020-2904 in MySQL Server
Summary
by MITRE
Vulnerability in the MySQL Server product of Oracle MySQL (component: Server: Optimizer). Supported versions that are affected are 8.0.19 and prior. Easily exploitable vulnerability allows high privileged attacker with network access via multiple protocols to compromise MySQL Server. Successful attacks of this vulnerability can result in unauthorized ability to cause a hang or frequently repeatable crash (complete DOS) of MySQL Server. CVSS 3.0 Base Score 4.9 (Availability impacts). CVSS Vector: (CVSS:3.0/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H).
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Analysis
by VulDB Data Team • 05/25/2024
The vulnerability identified as CVE-2020-2904 resides within the MySQL Server optimizer component of Oracle MySQL, affecting versions 8.0.19 and earlier. This represents a critical availability threat that operates at the core of database query processing, where the optimizer is responsible for determining the most efficient execution plan for SQL queries. The vulnerability manifests as a flaw in how the server handles certain query optimization scenarios, creating a pathway for malicious actors to disrupt database operations through carefully crafted inputs that trigger internal server failures.
This vulnerability operates under the Common Weakness Enumeration framework as CWE-121, which encompasses buffer overflow conditions that occur when a program writes data beyond the boundaries of a fixed-length buffer. The flaw specifically impacts the server's query optimization engine, where improper handling of certain data structures during query planning leads to memory corruption. Attackers with high privileges and network access can exploit this weakness by submitting malicious SQL queries that cause the optimizer to enter an invalid state, ultimately resulting in server crashes or hangs that effectively deny service to legitimate users.
The operational impact of CVE-2020-2904 extends beyond simple service disruption to create complete denial of service conditions that can severely impact database availability. The CVSS 3.0 score of 4.9 reflects the vulnerability's ability to cause a complete system outage through repeated crashes, making it particularly dangerous in production environments where database uptime is critical. The attack vector requires only network access and high privilege levels, meaning that authenticated attackers who have sufficient permissions within the database environment can leverage this vulnerability to bring down the entire MySQL server instance. This vulnerability aligns with ATT&CK technique T1499.004, which covers network denial of service attacks that target database systems.
The exploitation process involves crafting specific SQL queries that trigger the optimizer to process malformed data structures in a way that causes memory corruption and subsequent server instability. This type of vulnerability demonstrates the inherent complexity of database query optimizers, which must balance performance optimization with robust error handling. The fact that this vulnerability can be exploited through multiple protocols indicates that the flaw exists at a fundamental level within the server's core processing logic rather than being limited to specific network interfaces or access methods. Organizations affected by this vulnerability should implement immediate patching strategies, as the availability impact makes this a high-priority concern for database administrators and security teams.
Mitigation strategies for CVE-2020-2904 primarily focus on applying the vendor-provided security patches that address the specific memory handling issues within the optimizer component. System administrators should also implement network segmentation controls to limit access to database servers and reduce the attack surface available to potential adversaries. Monitoring solutions should be deployed to detect unusual patterns of database server crashes or hangs that might indicate exploitation attempts. Additionally, implementing proper access controls and privilege management ensures that only authorized users have the high-level permissions necessary to execute potentially dangerous SQL operations that could trigger this vulnerability. The vulnerability underscores the importance of regular security updates and the need for comprehensive testing of patches before deployment in production environments to prevent unexpected service disruptions.