CVE-2021-3436 Explained : Impact and Mitigation

Zephyr versions 1.14.2, 2.4.0, and 2.5.0 are affected by a vulnerability that allows overwriting an existing bond during the keys distribution phase when the identity address of the bond is known. This CVE has a base score of 4.3, with a medium severity level.

Understanding CVE-2021-3436

What is CVE-2021-3436?

CVE-2021-3436 is a vulnerability in Zephyr related to Bluetooth technology, where an attacker can potentially overwrite an existing bond during keys distribution when certain conditions are met.

The Impact of CVE-2021-3436

The impact of this vulnerability is rated with a base score of 4.3, falling under the medium severity level in terms of confidentiality, integrity, and availability.

Technical Details of CVE-2021-3436

Vulnerability Description

The vulnerability allows attackers to overwrite existing bonds during the keys distribution phase in Zephyr versions 1.14.2, 2.4.0, and 2.5.0, resulting in a compromise of system integrity.

Affected Systems and Versions

Zephyr versions >= 1.14.2, >= 2.4.0, and >= 2.5.0 are confirmed to be affected by this vulnerability, potentially impacting devices leveraging the affected versions.

Exploitation Mechanism

The exploitation involves manipulating the bond identity address during the keys distribution phase to overwrite existing bonds, leading to a security breach.

Mitigation and Prevention

Immediate Steps to Take

Users are advised to update their Zephyr installations to patched versions, which address the vulnerability and prevent potential exploitation.

Long-Term Security Practices

Incorporating secure coding practices, regular security audits, and staying updated with security advisories are crucial for maintaining a robust defense against such vulnerabilities.

Patching and Updates

Regularly checking for security updates from official sources and promptly applying patches to affected systems is vital in mitigating the risks associated with CVE-2021-3436.