CVE-2021-4120 : What You Need to Know

A detailed overview of CVE-2021-4120, an information security vulnerability in the snapd package by Canonical Ltd.

Understanding CVE-2021-4120

In this section, we will delve into what CVE-2021-4120 is, its impact, technical details, and mitigation strategies.

What is CVE-2021-4120?

The vulnerability in snapd 2.54.2 allows malicious snaps to inject arbitrary AppArmor policy rules, bypassing snap confinement mechanisms.

The Impact of CVE-2021-4120

The vulnerability poses a high risk as it permits unauthorized access and potential data breaches, affecting the confidentiality, integrity, and availability of systems.

Technical Details of CVE-2021-4120

Let's explore the specifics of the vulnerability, affected systems, and how attackers could exploit it.

Vulnerability Description

snapd 2.54.2 lacks proper validation of snap content interfaces, enabling malicious snaps to escape strict confinement via malformed AppArmor policy rules.

Affected Systems and Versions

The vulnerability affects snapd version 2.54.2, a package by Canonical Ltd., up to version 2.54.2.

Exploitation Mechanism

Attackers can exploit the flaw by crafting snaps with manipulated content interfaces, granting them unauthorized policy rule injection capabilities.

Mitigation and Prevention

To address CVE-2021-4120, it is crucial to take immediate action and implement robust security measures.

Immediate Steps to Take

Users are advised to update snapd to versions 2.54.3+18.04, 2.54.3+20.04, or 2.54.3+21.10.1 to mitigate the vulnerability.

Long-Term Security Practices

Implementing regular security updates, conducting security audits, and following best practices in snap usage can enhance overall system security.

Patching and Updates

Always stay updated with the latest security patches and software releases to defend against potential threats.