CVE-2021-34147 : Vulnerability Insights and Analysis

A vulnerability known as CVE-2021-34147 has been identified in the Bluetooth Classic implementation of the Cypress WICED BT stack through version 2.9.0 for CYW20735B1. This vulnerability can be exploited by attackers to exhaust device Bluetooth resources, leading to a crash.

Understanding CVE-2021-34147

This section provides detailed insights into the nature and implications of the CVE-2021-34147 vulnerability.

What is CVE-2021-34147?

The vulnerability lies in the improper handling of a malformed LMP timing accuracy response in the Bluetooth Classic implementation of the Cypress WICED BT stack. Attackers can exploit this flaw by initiating multiple reconnections to the link slave, causing a device crash.

The Impact of CVE-2021-34147

By leveraging this vulnerability, attackers can exhaust Bluetooth resources of the targeted device, subsequently leading to a crash. This can disrupt the normal operation of the device and potentially compromise its security.

Technical Details of CVE-2021-34147

This section delves into the technical specifics of CVE-2021-34147, including the vulnerability description, affected systems and versions, as well as the exploitation mechanism.

Vulnerability Description

The vulnerability arises from the inability of the Cypress WICED BT stack to handle a specific type of Bluetooth response, allowing attackers to trigger a crash through a sequence of crafted responses and sudden reconnections.

Affected Systems and Versions

CYW20735B1 devices running Cypress WICED BT stack versions up to 2.9.0 are vulnerable to this exploit, exposing them to the risk of resource exhaustion and subsequent crashes.

Exploitation Mechanism

Attackers can exploit CVE-2021-34147 by sending a series of carefully crafted LMP timing accuracy responses followed by repeated reconnections to the link slave, culminating in a device crash.

Mitigation and Prevention

To safeguard systems against the CVE-2021-34147 vulnerability, immediate steps must be taken alongside the adoption of long-term security practices through regular patching and updates.

Immediate Steps to Take

It is crucial to monitor Bluetooth connections, implement network segmentation, and restrict access to vulnerable devices to mitigate the risk of exploitation.

Long-Term Security Practices

Employing security best practices such as regular security assessments, network monitoring, and training personnel on identifying and responding to potential threats can bolster long-term defenses.

Patching and Updates

Vendor-released patches and updates addressing the CVE-2021-34147 vulnerability should be promptly applied to affected devices to eliminate the risk of exploitation and ensure system integrity.