CVE-2020-14567 in MySQL Server
Summary
by MITRE
Vulnerability in the MySQL Server product of Oracle MySQL (component: Server: Replication). 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 3.1 Base Score 4.9 (Availability impacts). CVSS Vector: (CVSS:3.1/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 • 11/02/2020
The vulnerability identified as CVE-2020-14567 represents a significant availability risk within Oracle MySQL Server's replication functionality. This issue affects critical database infrastructure components that are widely deployed across enterprise environments where data consistency and system uptime are paramount. The vulnerability resides specifically within the Server: Replication component of MySQL, making it particularly dangerous for systems that rely heavily on database replication for disaster recovery, load balancing, or data synchronization purposes. The affected versions include all 5.7.x releases up to 5.7.29 and all 8.0.x releases up to 8.0.19, indicating this flaw has been present for an extended period and likely affects a substantial portion of MySQL deployments in production environments.
The technical nature of this vulnerability stems from insufficient input validation and error handling within the replication mechanism that processes network protocols. When a high privileged attacker with network access attempts to exploit this weakness through multiple protocols, the system becomes susceptible to malformed replication requests that trigger internal state corruption. This flaw allows for complete denial of service conditions where the MySQL server either hangs indefinitely or experiences frequently repeatable crashes that can be triggered repeatedly by an attacker. The vulnerability's exploitability is rated as easily accessible due to the requirement of only network access and high privilege levels, meaning that authenticated users with appropriate permissions can leverage this weakness without requiring specialized tools or extensive reconnaissance. The underlying mechanism appears to involve improper handling of replication events that causes the server process to enter an unrecoverable state during replication processing.
The operational impact of this vulnerability extends far beyond simple service disruption, as MySQL servers are fundamental to most enterprise applications and web services. When a MySQL server experiences complete denial of service through this vulnerability, it can result in cascading failures throughout dependent systems that rely on database connectivity for their operations. Organizations using MySQL replication for critical business processes face severe operational risks, including potential data synchronization failures, application downtime, and service level agreement violations. The availability impact score of 4.9 on the CVSS 3.1 scale indicates a moderate to high severity threat that can significantly affect business continuity. This vulnerability particularly impacts systems where replication is used for high availability configurations, as the compromised server can no longer maintain its replication role, potentially leading to data inconsistencies across the entire replication topology.
Security mitigations for CVE-2020-14567 should focus on immediate patching strategies and network-level controls to prevent exploitation. Organizations must prioritize applying the official Oracle MySQL patches that address this specific replication flaw, as these updates contain the necessary code modifications to prevent the malformed replication requests from causing server crashes. Network segmentation and access controls should be implemented to limit which users and systems can initiate replication connections, reducing the attack surface available to potential attackers. Monitoring solutions should be enhanced to detect unusual replication activity patterns that might indicate exploitation attempts, particularly around replication event processing and server state changes. The vulnerability aligns with CWE-20 (Improper Input Validation) and CWE-362 (Concurrent Execution using Shared Resource with Improper Synchronization) categories, indicating fundamental flaws in how the system handles concurrent replication operations and input validation. From an ATT&CK framework perspective, this vulnerability maps to T1499.004 (Endpoint Denial of Service) and potentially T1566.001 (Phishing) if attackers leverage it as part of broader compromise campaigns. Organizations should also consider implementing database firewalls and intrusion detection systems that can monitor for replication protocol anomalies and prevent exploitation attempts before they can cause system-wide outages.