CVE-2022-21617: Oracle MySQL Server DoS Vulnerability

CVE-2022-21617 Overview

CVE-2022-21617 is a vulnerability in the MySQL Server product of Oracle MySQL, specifically affecting the Server: Connection Handling component. This flaw allows a high-privileged attacker with network access to cause a complete denial of service condition against affected MySQL Server instances. The vulnerability is classified as easily exploitable, requiring no user interaction to execute successfully.

Critical Impact

Successful exploitation allows attackers with administrative privileges to cause a hang or frequently repeatable crash of MySQL Server, resulting in complete denial of service to database operations.

Affected Products

• Oracle MySQL versions 5.7.39 and prior
• Oracle MySQL versions 8.0.30 and prior
• NetApp OnCommand Insight
• NetApp OnCommand Workflow Automation

Discovery Timeline

• 2022-10-18 - CVE-2022-21617 published to NVD
• 2024-11-21 - Last updated in NVD database

Technical Details for CVE-2022-21617

Vulnerability Analysis

This vulnerability resides within the Connection Handling component of Oracle MySQL Server. When exploited, it allows an authenticated attacker with high-level privileges (such as database administrators) to manipulate connection handling mechanisms in a way that destabilizes the server. The attack can be executed remotely over the network using multiple protocols supported by MySQL.

The vulnerability exclusively impacts system availability without affecting data confidentiality or integrity. An attacker cannot use this flaw to access or modify sensitive data; however, they can effectively render the database server inoperable through repeated crashes or system hangs.

Root Cause

The root cause stems from improper handling of connection requests within the MySQL Server's connection management subsystem. When specific conditions are met during connection handling operations, the server fails to properly manage resources or validate states, leading to an exploitable denial of service condition. The exact technical details have not been fully disclosed by Oracle, which classifies this under "NVD-CWE-noinfo."

Attack Vector

The attack vector for CVE-2022-21617 is network-based, meaning an attacker must have network connectivity to the MySQL Server instance. The attack requires:

1. High Privileges: The attacker must possess administrative-level access to the MySQL server
2. Network Access: Remote connectivity to the target MySQL instance via supported protocols
3. No User Interaction: The attack does not require any victim interaction

The exploitation process involves sending specially crafted requests that trigger the connection handling flaw. While specific exploitation techniques have not been publicly documented, the vulnerability can be triggered through normal MySQL connection protocols when conditions align.

Detection Methods for CVE-2022-21617

Indicators of Compromise

• Unexpected MySQL server crashes or service restarts without apparent cause
• Abnormal connection handling errors in MySQL error logs
• Repeated server hangs during periods of administrative activity
• Unusual patterns of privileged account connections preceding service disruptions

Detection Strategies

• Monitor MySQL error logs for connection handling exceptions and crash reports
• Implement database activity monitoring (DAM) to track administrative account usage patterns
• Configure alerting on MySQL service availability interruptions and automatic restarts
• Review audit logs for suspicious administrative operations from unexpected sources

Monitoring Recommendations

• Enable comprehensive logging for MySQL connection events and administrative actions
• Deploy network monitoring to detect anomalous traffic patterns to MySQL ports (3306/TCP by default)
• Implement real-time alerting for MySQL service state changes and process terminations
• Correlate authentication events with service availability metrics to identify exploitation attempts

How to Mitigate CVE-2022-21617

Immediate Actions Required

• Upgrade Oracle MySQL Server to versions newer than 5.7.39 (for 5.7.x branch) or 8.0.30 (for 8.0.x branch)
• Review and restrict administrative privileges to only essential personnel
• Implement network segmentation to limit access to MySQL Server instances
• Apply vendor patches as described in the Oracle Critical Patch Update October 2022

Patch Information

Oracle has addressed this vulnerability in their October 2022 Critical Patch Update (CPU). Administrators should apply the relevant patches from the Oracle Security Alert. For NetApp products, refer to the NetApp Security Advisory NTAP-20221028-0013 for specific remediation guidance. Fedora users should apply updates as announced in the Fedora Package Announcements.

Workarounds

• Restrict network access to MySQL Server to only trusted IP addresses using firewall rules
• Implement strict privilege management and audit high-privileged account usage
• Enable MySQL audit plugins to log all administrative operations for forensic purposes
• Consider deploying MySQL behind a proxy layer that can detect and block anomalous connection patterns

# MySQL configuration recommendations for hardening
# Add to my.cnf or my.ini configuration file

# Restrict bind address to specific interfaces
bind-address = 127.0.0.1

# Limit maximum connections to prevent resource exhaustion
max_connections = 150

# Enable error logging for troubleshooting
log_error = /var/log/mysql/error.log

# Enable general query log for auditing (use cautiously in production)
general_log = 1
general_log_file = /var/log/mysql/mysql.log