CVE-2020-2765 in MySQL Server
Summary
by MITRE
Vulnerability in the MySQL Server product of Oracle MySQL (component: Server: Optimizer). Supported versions that are affected are 5.7.29 and prior and 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-2020-2765 resides within the MySQL Server optimizer component of Oracle MySQL database systems. This flaw affects specific versions including all 5.7.x releases prior to 5.7.29 and all 8.0.x releases prior to 8.0.19, representing a significant exposure across multiple MySQL server versions. The vulnerability operates at a fundamental level within the database server's query optimization engine, which is responsible for determining the most efficient execution path for database queries. The affected optimizer component processes complex query structures and logical operations that form the backbone of database transaction processing, making this a critical weakness in the database infrastructure.
The technical nature of this vulnerability stems from improper handling of certain query optimization scenarios that can lead to memory corruption or resource exhaustion conditions. Attackers with high-privileged network access can exploit this weakness by crafting specific database queries that trigger the flawed optimization path. The vulnerability's exploitability is classified as easily accessible due to the minimal prerequisites required for successful exploitation, which only necessitates network connectivity to the MySQL server and elevated privileges within the database system. This makes the vulnerability particularly dangerous as it can be leveraged by attackers who have already gained some level of access to the database environment but do not require additional authentication mechanisms to be compromised.
The operational impact of CVE-2020-2765 manifests as a complete denial of service condition that can either cause the MySQL server to hang indefinitely or repeatedly crash, effectively rendering the database unavailable to legitimate users and applications. This type of vulnerability represents a serious availability threat that can severely disrupt business operations, particularly in environments where database uptime is critical for application functionality. The CVSS 3.0 scoring of 4.9 reflects the moderate severity of the availability impact, though the actual business disruption can be substantial depending on the criticality of the affected database systems. The vulnerability's potential for causing repeated crashes means that even a single successful exploit can result in prolonged service interruption, making it particularly damaging in production environments.
Security practitioners should prioritize patching affected MySQL installations to address this vulnerability, as the remediation process involves updating to versions that contain the fixed optimizer component. Organizations should implement network segmentation and access controls to limit exposure of MySQL servers to untrusted networks, reducing the attack surface for potential exploitation attempts. The vulnerability aligns with CWE-121, which addresses stack-based buffer overflow conditions, and represents a classic example of how optimization engine flaws can create denial of service vulnerabilities. From an attack framework perspective, this vulnerability would typically be categorized under the attack technique of resource exhaustion within the MITRE ATT&CK framework, specifically targeting the availability pillar of the CIA triad. Regular security assessments and database server monitoring should include verification of MySQL version compliance to prevent exploitation of this and similar vulnerabilities in database infrastructure.