CVE-2023-22079 - Critical Vulnerability in MySQL Server 8..34 and Prior, Allowing for Complete Denial-of-Service Attacks

A significant vulnerability (CVE-2023-22079) has been discovered in the MySQL Server product of Oracle MySQL, specifically within the Optimizer component. This vulnerability affects MySQL Server versions 8..34 and earlier. A successful exploitation of this vulnerability can allow low privileged attackers with network access to cause a hang or frequently repeatable crash of MySQL Server. It is important for MySQL administrators and developers to understand the details of this security issue and apply remedies to prevent potential attacks.

Vulnerability Details

According to the Common Vulnerabilities and Exposures (CVE) entry, the vulnerability has the following CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H. This means that the Base Score is 6.5 (Availability impacts), indicating a severe impact on the availability of the affected server.

The primary source of this vulnerability is in the MySQL Server's Optimizer component. An attacker can compromise the MySQL Server by leveraging this vulnerability through low-privilege network access via multiple protocols.

Exploitation of this vulnerability results in unauthorized ability to cause a hang or frequently repeatable crash (complete denial-of-service or DOS) of MySQL Server, effectively disrupting the normal functioning of the server and potentially causing data loss or temporary shutdown of services.

Code Snippet

While the actual exploit code has not been published, understanding the basic operation of the MySQL Optimizer helps illustrate the potential exploitation path:

SELECT * FROM table_A
JOIN table_B ON table_A.ID = table_B.ID
WHERE table_A.value > 100;

In this SQL query example, the MySQL Optimizer would typically evaluate the most efficient execution plan for fetching the required data. However, a specially crafted query or input by the attacker can potentially overload the Optimizer and lead to the aforementioned crash or hang.

Original References

- CVE-2023-22079 - Official CVE entry in the MITRE database.
- Oracle Critical Patch Update Advisory - April 2023 - Oracle's official security advisory containing details about the vulnerability and links to available patches.

Mitigation Steps

The primary step required to mitigate this vulnerability is to update the affected MySQL Server installations to a patched and secure version, as provided by Oracle. For version 8..34 and earlier, users should update to the latest available MySQL 8.x release or consider upgrading to MySQL 9.x if it addresses the vulnerability and is compatible with their specific environment.

Secondly, MySQL administrators should ensure that proper access controls are in place, limiting the scope of potential attackers. This may involve tightening network rules to allow only trusted sources to connect to the MySQL server or implementing strict user authentication and privilege management to minimize the risk of unauthorized users gaining low-level access to the server.

Conclusion

CVE-2023-22079 is a critical vulnerability within the MySQL Server's Optimizer component, affecting versions 8..34 and earlier. Successful exploitation can result in complete DOS of MySQL Server. Users of vulnerable versions should immediately upgrade their installations to a secure release and ensure proper access controls are in place to protect their databases from potential attacks.

Timeline

Published on: 10/17/2023 22:15:00 UTC
Last modified on: 10/19/2023 09:45:00 UTC