CVE-2020-14760 Overview
CVE-2020-14760 is a vulnerability in the MySQL Server product of Oracle MySQL, specifically affecting the Server: Optimizer component. This vulnerability allows a high-privileged attacker with network access via multiple protocols to compromise MySQL Server, resulting in denial of service conditions and unauthorized data modification capabilities.
Critical Impact
Successful exploitation can cause a complete denial of service (hang or frequently repeatable crash) of MySQL Server, as well as unauthorized update, insert, or delete access to some MySQL Server accessible data.
Affected Products
- Oracle MySQL Server version 5.7.31 and prior
- Oracle MySQL (all editions utilizing the Server: Optimizer component)
- Systems running vulnerable MySQL versions with network-accessible database services
Discovery Timeline
- October 21, 2020 - CVE-2020-14760 published to NVD
- November 21, 2024 - Last updated in NVD database
Technical Details for CVE-2020-14760
Vulnerability Analysis
This vulnerability resides in the Server: Optimizer component of Oracle MySQL. The Optimizer is responsible for query execution planning and optimization, making it a critical component for database performance and functionality. The flaw allows an authenticated attacker with high privileges to trigger conditions that result in service disruption and limited data integrity impacts.
The vulnerability is easily exploitable over the network via multiple protocols that MySQL supports. While the attacker requires high-level privileges to exploit this vulnerability, the impact on availability is severe, potentially causing complete service interruption through hangs or repeatable crashes. Additionally, the vulnerability permits unauthorized modification of some accessible data, though confidentiality is not impacted.
Root Cause
The vulnerability stems from improper handling within the MySQL Server's Optimizer component. While Oracle has not disclosed specific technical details about the root cause, the issue appears to be related to how the Optimizer processes certain queries or optimization paths, leading to resource exhaustion or crash conditions when triggered by a privileged attacker.
Attack Vector
The attack vector is network-based, meaning an attacker can exploit this vulnerability remotely over the network without any user interaction. The attacker must possess high-level privileges on the MySQL Server, such as administrative or DBA-level access. Once authenticated, the attacker can send specially crafted queries or commands that trigger the vulnerable code path in the Optimizer component, resulting in service disruption.
The exploitation does not require complex conditions and can be performed through standard MySQL network protocols. The scope is unchanged, meaning the impact is confined to the vulnerable MySQL Server instance.
Detection Methods for CVE-2020-14760
Indicators of Compromise
- Unexpected MySQL Server crashes or hangs, particularly during query optimization phases
- Unusual database restart events or service recovery attempts
- Unauthorized data modifications detected in audit logs
- High-privileged account activity from unexpected sources or at unusual times
Detection Strategies
- Monitor MySQL error logs for repeated crash signatures related to the Optimizer component
- Implement database activity monitoring (DAM) to track privileged user operations
- Configure alerting for MySQL service interruptions or automatic restarts
- Review authentication logs for high-privileged account access patterns
Monitoring Recommendations
- Enable MySQL general query log to capture queries that may trigger the vulnerability
- Deploy network monitoring to detect anomalous traffic patterns to MySQL ports
- Implement real-time alerting for MySQL service availability metrics
- Configure SIEM integration to correlate database crashes with user activity
How to Mitigate CVE-2020-14760
Immediate Actions Required
- Upgrade MySQL Server to version 5.7.32 or later, which contains the security fix
- Review and restrict high-privilege account access to only necessary personnel
- Implement network segmentation to limit MySQL Server network exposure
- Enable audit logging to track privileged operations on the database
Patch Information
Oracle addressed this vulnerability in the Oracle Critical Patch Update October 2020. Organizations should apply the patch by upgrading to MySQL Server version 5.7.32 or later. Additional security advisories have been published by Gentoo Linux and NetApp for their respective distributions and products.
Workarounds
- Restrict network access to MySQL Server using firewall rules to limit exposure
- Implement strict privilege management policies to minimize high-privileged accounts
- Monitor and audit all high-privilege database operations for suspicious activity
- Consider placing MySQL Server behind a database proxy with query filtering capabilities
# Configuration example - Restrict MySQL network access
# In my.cnf or mysqld.cnf:
bind-address = 127.0.0.1
# Or specify trusted network interface only
# bind-address = 10.0.0.5
# Enable general query log for monitoring
general_log = 1
general_log_file = /var/log/mysql/mysql.log
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
