CVE-2020-2928 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-2020-2928 resides within the MySQL Server optimizer component of Oracle MySQL, affecting versions 8.0.19 and earlier. This represents a critical availability-focused weakness that operates at the server level, specifically targeting the query optimization engine that processes and executes database operations. The vulnerability manifests as a flaw in how MySQL handles certain optimizer operations, creating conditions where maliciously crafted queries can trigger system instability. The affected component operates within the core database processing pipeline, making it particularly dangerous as it impacts fundamental database functionality and can be exploited through multiple network protocols including TCP/IP and Unix domain sockets.
The technical nature of this vulnerability stems from improper handling of specific optimizer scenarios that lead to resource exhaustion or memory corruption conditions within the MySQL server process. Attackers with high-privileged network access can leverage this weakness by submitting carefully constructed SQL queries that exploit the optimizer's decision-making process. The flaw essentially allows an attacker to cause the MySQL server to enter an unrecoverable state where it either hangs indefinitely or crashes repeatedly, resulting in complete denial of service. This type of vulnerability falls under CWE-121, which categorizes buffer overflow conditions, and more specifically aligns with CWE-129, concerning improper validation of array indices, as the optimizer may not properly validate memory access patterns during query processing.
From an operational impact perspective, this vulnerability presents a significant risk to database availability and system reliability. Organizations relying on MySQL for critical business operations face potential downtime and service disruption when this vulnerability is exploited, particularly in environments where database availability is paramount. The CVSS 3.0 score of 4.9 indicates a moderate to high severity impact with the availability vector set at high, reflecting the complete denial of service that can occur. The vulnerability requires an attacker with high privileges and network access, suggesting that internal network compromise or legitimate administrative access would be necessary for exploitation, though this still represents a serious threat vector.
The attack surface for this vulnerability extends across multiple network protocols, making it particularly concerning for environments with diverse network access points. The fact that it can be exploited through multiple protocols indicates that traditional network segmentation and access controls may not fully protect against this specific threat. Organizations should consider implementing network monitoring to detect unusual query patterns or resource consumption spikes that might indicate exploitation attempts. Additionally, the vulnerability's impact on system stability means that even partial exploitation could result in extended service interruptions that affect business continuity. This aligns with ATT&CK technique T1499.004, which covers network denial of service attacks, and represents a significant concern for database administrators managing critical infrastructure systems.
Mitigation strategies for CVE-2020-2928 should prioritize immediate patching of affected MySQL versions to 8.0.20 or later, which contains the necessary fixes for the optimizer vulnerability. Organizations should also implement network access controls and privilege management to limit who can submit queries to the database server, reducing the attack surface for potential exploitation. Database administrators should monitor query execution patterns and implement query timeouts to prevent prolonged resource consumption. Regular vulnerability assessments and penetration testing should be conducted to identify similar optimizer-related issues that might exist in other database components. The implementation of database activity monitoring tools can help detect anomalous behavior patterns that might indicate attempted exploitation of this vulnerability. Organizations should also consider implementing database firewalls or query filtering mechanisms to prevent potentially malicious queries from reaching the optimizer component.