CVE-2023-21876 Explained : Impact and Mitigation

This article provides detailed information about CVE-2023-21876, a vulnerability identified in Oracle's MySQL Server.

Understanding CVE-2023-21876

CVE-2023-21876 is a vulnerability in the MySQL Server product of Oracle MySQL, specifically within the Server Optimizer component. The vulnerability allows a high-privileged attacker with network access through multiple protocols to compromise the MySQL Server. Successful exploitation of this vulnerability can lead to unauthorized actions causing the server to hang or crash frequently, resulting in a denial-of-service (DOS) scenario.

What is CVE-2023-21876?

The vulnerability in CVE-2023-21876 affects Oracle's MySQL Server, specifically versions 8.0.31 and earlier. It is classified as an easily exploitable vulnerability that can be leveraged by a high-privileged attacker with network access via various protocols. The CVSS 3.1 Base Score for this vulnerability is 4.9, with a focus on availability impacts.

The Impact of CVE-2023-21876

If successfully exploited, CVE-2023-21876 can enable an attacker to compromise the MySQL Server. This compromise can lead to unauthorized actions that cause the server to hang or crash repeatedly, resulting in a denial-of-service scenario. The impact of this vulnerability is primarily on the availability of the MySQL Server.

Technical Details of CVE-2023-21876

The following technical details provide insights into the vulnerability, affected systems and versions, as well as the exploitation mechanism:

Vulnerability Description

The vulnerability in MySQL Server (Oracle MySQL) allows a high-privileged attacker with network access via multiple protocols to compromise the server. Successful exploitation can lead to the unauthorized ability to hang or crash the MySQL Server, resulting in a complete denial-of-service scenario.

Affected Systems and Versions

The vulnerability impacts Oracle's MySQL Server, particularly affecting versions 8.0.31 and prior.

Exploitation Mechanism

Exploitation of CVE-2023-21876 requires a high-privileged attacker with network access through various protocols. By leveraging this access, the attacker can compromise the MySQL Server and cause it to hang or crash repeatedly, leading to a denial-of-service situation.

Mitigation and Prevention

To address the CVE-2023-21876 vulnerability, it is crucial to implement immediate steps for mitigation and establish long-term security practices:

Immediate Steps to Take

Update MySQL Server to a non-affected version.
Implement network security measures to restrict access to the MySQL Server.
Monitor server performance for any unusual activity that may indicate exploitation attempts.

Long-Term Security Practices

Regularly update and patch the MySQL Server to prevent known vulnerabilities.
Conduct security awareness training for server administrators to enhance security practices.
Implement network segmentation to limit the impact of potential attacks on the MySQL Server.

Patching and Updates

Oracle has released security updates to address the CVE-2023-21876 vulnerability in MySQL Server. It is crucial to apply these patches promptly to secure the server infrastructure and prevent potential exploitation.