CVE-2021-31611 Explained : Impact and Mitigation

A vulnerability has been discovered in the Bluetooth Classic implementation on Zhuhai Jieli AC690X and AC692X devices. Attackers in radio range can exploit this flaw to deadlock a device via a crafted LMP packet, requiring manual reboot for communication restoration.

Understanding CVE-2021-31611

This section will provide insights into the impact, technical details, and mitigation strategies related to CVE-2021-31611.

What is CVE-2021-31611?

The Bluetooth Classic implementation on Zhuhai Jieli AC690X and AC692X devices is susceptible to a deadlock issue caused by a specific sequence of LMP packets. This vulnerability enables attackers within radio range to disrupt device functionality, necessitating a manual reboot.

The Impact of CVE-2021-31611

Exploitation of this vulnerability by malicious actors can result in a denial of service condition on affected devices. By sending a crafted LMP packet following an out-of-order LMP Setup procedure, attackers can render the device unresponsive, requiring manual intervention from the user to restore normal operation.

Technical Details of CVE-2021-31611

In this section, we delve into the vulnerability description, affected systems and versions, as well as the exploitation mechanism.

Vulnerability Description

The vulnerability exists in the way Zhuhai Jieli AC690X and AC692X devices handle out-of-order LMP Setup procedures followed by malformed LMP packets. This flaw can be exploited by attackers within radio proximity to trigger a deadlock situation in the device.

Affected Systems and Versions

The Bluetooth Classic implementation on Zhuhai Jieli AC690X and AC692X devices is affected by this vulnerability. Specific versions that do not properly handle the LMP packet sequence are at risk.

Exploitation Mechanism

Attackers can exploit this vulnerability by sending a malicious LMP packet after an out-of-order LMP Setup procedure, causing the device to become unresponsive until manually rebooted.

Mitigation and Prevention

This section outlines immediate steps to take, long-term security practices, and the importance of timely patching and updates.

Immediate Steps to Take

To mitigate the risk associated with CVE-2021-31611, users of affected devices should consider limiting exposure to untrusted Bluetooth connections and promptly reboot the device if it becomes unresponsive.

Long-Term Security Practices

Implementing strict access controls, regularly updating device firmware, and monitoring Bluetooth connections are crucial for enhancing the security posture of Bluetooth-enabled devices.

Patching and Updates

Manufacturers should release patches addressing the vulnerability in Bluetooth Classic implementation on Zhuhai Jieli AC690X and AC692X devices. Users are advised to apply these patches promptly to safeguard their devices against potential exploitation.