CVE-2021-20106 Explained : Impact and Mitigation

Nessus Agent versions 8.2.5 and earlier have been identified to have a privilege escalation vulnerability that could be exploited by a Nessus administrator user to upload a malicious file, potentially leading to gaining administrator privileges on the Nessus host.

Understanding CVE-2021-20106

This section delves into the details of the CVE-2021-20106 vulnerability.

What is CVE-2021-20106?

CVE-2021-20106 is a Local Privilege Escalation vulnerability found in Nessus Agent versions 8.2.5 and earlier. It allows a Nessus administrator user to execute a specially crafted file, enabling the elevation of privileges on the Nessus host.

The Impact of CVE-2021-20106

The impact of this vulnerability is severe as it grants unauthorized users the ability to potentially gain full control over the Nessus host, compromising its security and integrity.

Technical Details of CVE-2021-20106

In this section, we explore the technical aspects of CVE-2021-20106.

Vulnerability Description

The vulnerability in Nessus Agent versions 8.2.5 and earlier enables a privilege escalation attack by uploading a malicious file to the host, resulting in elevated administrator privileges.

Affected Systems and Versions

Nessus Agent versions 8.2.5 and earlier are affected by this vulnerability, making systems with these versions at risk of exploitation.

Exploitation Mechanism

The exploitation involves the uploading of a specially crafted file by a Nessus administrator user, which triggers the privilege escalation process on the host.

Mitigation and Prevention

This section focuses on the actions to mitigate and prevent CVE-2021-20106.

Immediate Steps to Take

Users are advised to update Nessus Agent to a secure version beyond 8.2.5, apply necessary security configurations, and monitor for any suspicious activities.

Long-Term Security Practices

Implementing strict access controls, regular security assessments, and maintaining up-to-date software can help in preventing similar vulnerabilities in the future.

Patching and Updates

Regularly check for security updates and patches released by Tenable for Nessus Agent to ensure the system is protected from known vulnerabilities.