CVE-2021-3966 Explained : Impact and Mitigation

A USB Bluetooth device ACL read CB buffer overflow vulnerability has been identified in the Zephyr project's RTOS, affecting versions up to v3.0. This article provides an overview of CVE-2021-3966, including its impact, technical details, and mitigation strategies.

Understanding CVE-2021-3966

This section will cover the details of the CVE-2021-3966 vulnerability.

What is CVE-2021-3966?

The CVE-2021-3966 vulnerability is described as a USB device Bluetooth class buffer overflow related to the implementation of net_buf_add_mem.

The Impact of CVE-2021-3966

The vulnerability has a CVSS base score of 9.6, classifying it as critical. It could allow an attacker to execute arbitrary code on affected systems, leading to potential integrity and availability issues.

Technical Details of CVE-2021-3966

Let's delve into the technical aspects of CVE-2021-3966.

Vulnerability Description

CVE-2021-3966 is categorized as a heap-based buffer overflow (CWE-122), which could be exploited by an attacker to trigger a denial of service (DoS) or execute malicious code on the target system.

Affected Systems and Versions

The vulnerability impacts the Zephyr RTOS project, specifically affecting versions up to v3.0 that utilize USB Bluetooth devices.

Exploitation Mechanism

The vulnerability occurs due to inadequate bounds checking on input data received from USB Bluetooth devices, leading to a buffer overflow condition that can be abused by an attacker.

Mitigation and Prevention

Discover the necessary steps to mitigate the risks associated with CVE-2021-3966.

Immediate Steps to Take

Users are advised to apply the latest security patches provided by Zephyr project RTOS to address the CVE-2021-3966 vulnerability. Additionally, minimizing exposure of vulnerable systems to untrusted USB Bluetooth devices is recommended.

Long-Term Security Practices

Implement secure coding practices, conduct regular security assessments, and monitor for any abnormal network activity to enhance the overall security posture and prevent similar vulnerabilities in the future.

Patching and Updates

Stay informed about security updates and advisories from the Zephyr project RTOS and apply patches promptly to ensure that systems are protected against known vulnerabilities.