CVE-2020-2574: Oracle MySQL Client DOS Vulnerability

CVE-2020-2574 Overview

CVE-2020-2574 is a denial of service vulnerability in the MySQL Client product of Oracle MySQL, specifically affecting the C API component. This vulnerability allows an unauthenticated attacker with network access to cause a hang or frequently repeatable crash of the MySQL Client, resulting in complete denial of service. While the vulnerability is considered difficult to exploit due to specific conditions required for successful exploitation, its network-accessible nature and lack of authentication requirements make it a concern for organizations running affected MySQL versions.

Critical Impact

Successful exploitation can result in complete denial of service of MySQL Client applications, potentially disrupting database connectivity for critical business applications.

Affected Products

• Oracle MySQL 5.6.46 and prior
• Oracle MySQL 5.7.28 and prior
• Oracle MySQL 8.0.18 and prior
• MariaDB (multiple versions)
• NetApp Active IQ Unified Manager
• NetApp OnCommand Insight
• NetApp OnCommand Workflow Automation
• NetApp SnapCenter
• Canonical Ubuntu Linux 16.04, 18.04, 19.10
• openSUSE Leap 15.1

Discovery Timeline

• January 15, 2020 - CVE-2020-2574 published to NVD
• November 21, 2024 - Last updated in NVD database

Technical Details for CVE-2020-2574

Vulnerability Analysis

This vulnerability resides in the C API component of the MySQL Client, which serves as the fundamental interface for client applications to communicate with MySQL database servers. The flaw allows remote attackers to trigger a denial of service condition without requiring any authentication credentials. While NVD has not classified this under a specific CWE category, the vulnerability's behavior—causing hangs or repeatable crashes—suggests potential issues in connection handling or protocol processing within the C API.

The attack requires network access but can be conducted through multiple protocols supported by MySQL, expanding the potential attack surface. Although the vulnerability does not impact confidentiality or integrity of data, the availability impact is rated as high, meaning successful exploitation can completely disrupt MySQL Client operations.

Root Cause

The root cause stems from improper handling within the MySQL Client C API component. While specific technical details have not been publicly disclosed by Oracle, the vulnerability appears to involve conditions that allow remote network requests to trigger resource exhaustion or exception handling failures, leading to client application crashes or unresponsive states.

Attack Vector

The attack vector is network-based, allowing an unauthenticated attacker to target MySQL Client applications remotely. The exploitation flow involves:

1. The attacker identifies systems running vulnerable MySQL Client versions
2. Crafted network requests are sent to the target through any of the multiple protocols supported by MySQL
3. The malicious requests trigger the vulnerability in the C API component
4. The MySQL Client application enters a hang state or crashes repeatedly

Due to the high attack complexity rating, successful exploitation may require specific timing, configuration, or environmental conditions to achieve the denial of service impact.

Detection Methods for CVE-2020-2574

Indicators of Compromise

• Unexpected MySQL Client application crashes or hangs during normal database operations
• Repeated connection failures or timeouts from client applications to MySQL servers
• Unusual network traffic patterns targeting MySQL Client instances
• Process dumps or crash logs indicating failures in MySQL C API library components

Detection Strategies

• Monitor MySQL Client applications for unexpected terminations or non-responsive states
• Implement network intrusion detection rules to identify anomalous MySQL protocol traffic
• Deploy application-level monitoring to track MySQL Client connection success rates and latency
• Review system logs for segmentation faults or crashes related to MySQL client libraries

Monitoring Recommendations

• Configure alerting on MySQL Client process crashes using endpoint monitoring solutions
• Establish baseline metrics for MySQL Client connection behavior and alert on deviations
• Enable verbose logging for MySQL Client applications in production environments to capture pre-crash conditions
• Implement health checks for applications dependent on MySQL Client connectivity

How to Mitigate CVE-2020-2574

Immediate Actions Required

• Inventory all systems running MySQL Client versions 5.6.46 and prior, 5.7.28 and prior, or 8.0.18 and prior
• Apply the Oracle Critical Patch Update from January 2020 to all affected MySQL installations
• Update MariaDB installations to patched versions as applicable
• Review network segmentation to limit exposure of MySQL Client systems to untrusted networks

Patch Information

Oracle addressed this vulnerability in the Oracle January 2020 Critical Patch Update. Organizations should upgrade to the following minimum versions:

• MySQL 5.6.47 or later
• MySQL 5.7.29 or later
• MySQL 8.0.19 or later

Additional vendor advisories are available from:

• NetApp Security Advisory NTAP-20200122-0002
• Ubuntu Security Notice USN-4250-1
• Ubuntu Security Notice USN-4250-2
• Gentoo GLSA 2021-05-27
• openSUSE Security Announcement

Workarounds

• Implement network access controls to restrict MySQL Client access to trusted networks only
• Deploy firewall rules to limit inbound connections to MySQL Client applications from unknown sources
• Consider using connection pooling and automatic restart mechanisms to minimize impact of potential crashes
• Enable application-level retry logic to handle temporary client failures gracefully

# Example: Restrict MySQL traffic using iptables
# Allow MySQL connections only from trusted network segments
iptables -A INPUT -p tcp --dport 3306 -s 192.168.1.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 3306 -j DROP