CVE-2022-0396 Explained : Impact and Mitigation

A detailed analysis of CVE-2022-0396 revealing information about a Denial of Service (DoS) vulnerability in BIND that affects certain versions.

Understanding CVE-2022-0396

This section provides insights into the vulnerability, its impact, technical details, and mitigation strategies.

What is CVE-2022-0396?

CVE-2022-0396 refers to a Denial of Service (DoS) vulnerability in BIND affecting versions 9.16.11 to 9.16.26, 9.17.0 to 9.18.0, and versions 9.16.11-S1 to 9.16.26-S1 of the BIND Supported Preview Edition. The vulnerability arises from specifically crafted TCP streams causing connections to BIND to stay in CLOSE_WAIT status indefinitely.

The Impact of CVE-2022-0396

Exploiting this vulnerability can lead to excessive consumption of TCP connection slots, affecting the availability of affected BIND servers. It allows attackers to keep connections in an undesirable state even after the client terminates the connection, potentially leading to a Denial of Service condition.

Technical Details of CVE-2022-0396

In-depth technical information about the vulnerability is crucial for understanding the affected systems, exploitation mechanism, and preventive measures.

Vulnerability Description

The issue arises due to the mishandling of TCP streams in affected versions of BIND. By sending specifically crafted TCP packets, an attacker can cause connections to remain in CLOSE_WAIT status, impacting server resources.

Affected Systems and Versions

ISC BIND versions 9.16.11 to 9.16.26, 9.17.0 to 9.18.0, and versions 9.16.11-S1 to 9.16.26-S1 of the BIND Supported Preview Edition are vulnerable to this DoS condition. Ensure timely updates to secure your systems.

Exploitation Mechanism

Attackers exploit this vulnerability by crafting malicious TCP streams, causing affected BIND servers to keep connections open indefinitely, leading to resource exhaustion.

Mitigation and Prevention

Understanding how to mitigate the risk posed by CVE-2022-0396 is essential for maintaining the security of your systems.

Immediate Steps to Take

To address the vulnerability, configure BIND servers to use the default setting of 'keep-response-order { none; }' in all affected versions. No active exploits have been reported at present.

Long-Term Security Practices

Regularly monitor for updates and patches released by ISC. Implement robust network security measures to protect against potential DoS attacks and keep your systems secure.

Patching and Updates

Upgrade affected BIND versions to the latest patched releases, such as 9.16.27 and 9.18.1, to address the vulnerability effectively. ISC provides a special feature-preview branch, BIND Supported Preview Edition, for eligible support customers, which includes version 9.16.27-S1.