CVE-2020-8619 : Exploit Details and Defense Strategies

In ISC BIND9 versions BIND 9.11.14 -> 9.11.19, BIND 9.14.9 -> 9.14.12, BIND 9.16.0 -> 9.16.3, BIND Supported Preview Edition 9.11.14-S1 -> 9.11.19-S1, a buffer boundary check assertion in rdataset.c can fail incorrectly during zone transfer.

Understanding CVE-2020-8619

This CVE involves a vulnerability in ISC BIND9 versions that could lead to denial of service attacks.

What is CVE-2020-8619?

This CVE affects BIND9 versions and could allow an attacker to exploit a defect causing denial of service by introducing a specific record in a zone.

The Impact of CVE-2020-8619

CVSS Base Score: 4.9 (Medium)
Attack Vector: Network
Availability Impact: High
Privileges Required: High

Technical Details of CVE-2020-8619

This section provides more in-depth technical details about the vulnerability.

Vulnerability Description

The vulnerability arises when an asterisk character is present in an empty non-terminal location within the DNS graph, potentially leading to a denial of service condition.

Affected Systems and Versions

BIND 9.11.14 -> 9.11.19
BIND 9.14.9 -> 9.14.12
BIND 9.16.0 -> 9.16.3
BIND Supported Preview Edition 9.11.14-S1 -> 9.11.19-S1

Exploitation Mechanism

An attacker with the ability to change zone content could introduce a specific record to exploit the vulnerability and cause denial of service.

Mitigation and Prevention

It is crucial to take immediate steps to address and prevent the exploitation of this vulnerability.

Immediate Steps to Take

Upgrade to the patched release closest to your current BIND version: BIND 9.11.20, BIND 9.16.4
For BIND Supported Preview Edition users, upgrade to BIND 9.11.20-S1

Long-Term Security Practices

Regularly update BIND to the latest versions
Implement proper access controls and monitoring mechanisms

Patching and Updates

Ensure timely application of patches and updates to mitigate the risk of exploitation.