CVE-2020-8621 Explained : Impact and Mitigation

In BIND 9.14.0 -> 9.16.5, 9.17.0 -> 9.17.3, a vulnerability exists where a server configured with both QNAME minimization and 'forward first' can crash when receiving queries, potentially triggered by an attacker. This CVE affects BIND versions 9.14.0 to 9.17.3.

Understanding CVE-2020-8621

This CVE highlights a specific vulnerability in BIND versions that can lead to a server crash under certain configurations.

What is CVE-2020-8621?

The vulnerability arises when a server is set up with both QNAME minimization and 'forward first,' allowing an attacker to potentially crash the server by sending queries.

The Impact of CVE-2020-8621

The impact of this vulnerability is rated as HIGH, with a CVSS base score of 7.5. However, there are no known active exploits at the time of reporting.

Technical Details of CVE-2020-8621

This section delves into the technical aspects of the vulnerability.

Vulnerability Description

The vulnerability occurs in BIND versions 9.14.0 to 9.17.3, where specific server configurations can lead to a crash when processing queries.

Affected Systems and Versions

Affected Versions: 9.17.0
Unaffected Versions: 9.16.6, 9.17.4

Exploitation Mechanism

The vulnerability can be triggered by an attacker sending queries to a server configured with both QNAME minimization and 'forward first.'

Mitigation and Prevention

To address CVE-2020-8621, consider the following mitigation strategies:

Immediate Steps to Take

Upgrade to the patched release closest to your current version: BIND 9.16.6 or BIND 9.17.4

Long-Term Security Practices

Regularly update BIND to the latest version
Implement secure server configurations

Patching and Updates

Ensure you update BIND to the latest patched release to mitigate the vulnerability.