CVE-2021-3433 : Security Advisory and Response

This article provides detailed insights into CVE-2021-3433, focusing on the vulnerability, impact, technical details, and mitigation strategies.

Understanding CVE-2021-3433

CVE-2021-3433 is a vulnerability in Zephyr that leads to a deadlock due to an invalid channel map in CONNECT_IND. The affected versions include Zephyr v2.5.0 and later.

What is CVE-2021-3433?

The vulnerability in Zephyr versions >= v2.5.0 results in a deadlock situation due to improper handling of exceptional conditions related to the channel map in CONNECT_IND.

The Impact of CVE-2021-3433

With a CVSS v3.1 base score of 4, this vulnerability poses a moderate risk, with low attack complexity and vector being local. It does not impact confidentiality or integrity but affects availability.

Technical Details of CVE-2021-3433

This section delves into the specific technical aspects of the CVE.

Vulnerability Description

The vulnerability arises from an improper check or handling of exceptional conditions, as per CWE-703, leading to a deadlock scenario in Zephyr.

Affected Systems and Versions

Zephyr versions >= v2.5.0 are impacted by this vulnerability, affecting systems utilizing these versions.

Exploitation Mechanism

The exploitation requires local access and a certain level of complexity, involving manipulation of the channel map through CONNECT_IND.

Mitigation and Prevention

Protecting systems from CVE-2021-3433 requires immediate actions and long-term security practices.

Immediate Steps to Take

To mitigate the risk posed by this vulnerability, users are advised to implement the necessary patches and updates promptly.

Long-Term Security Practices

Building a robust security posture involves ongoing monitoring, threat intelligence integration, and regular security audits.

Patching and Updates

Ensuring that Zephyr installations are up to date with the latest security patches and version upgrades is crucial in addressing CVE-2021-3433.