CVE-2021-3564 : Exploit Details and Defense Strategies

A detailed overview of CVE-2021-3564, a vulnerability in the Linux kernel HCI device initialization subsystem that could allow a local user to crash the system.

Understanding CVE-2021-3564

This section provides insights into the impact, technical details, and mitigation steps related to CVE-2021-3564.

What is CVE-2021-3564?

CVE-2021-3564 is a double-free memory corruption flaw in the Linux kernel HCI device initialization subsystem. When a user attaches a malicious HCI TTY Bluetooth device, a local user could exploit this vulnerability to crash the system. The issue affects all Linux kernel versions starting from 3.13.

The Impact of CVE-2021-3564

The vulnerability can be leveraged by a local user to trigger a system crash. This could lead to denial of service or potential escalation of privileges on the affected system.

Technical Details of CVE-2021-3564

In this section, we dive deeper into the vulnerability description, affected systems, and the exploitation mechanism.

Vulnerability Description

The flaw arises due to improper handling of memory in the Linux kernel HCI device initialization subsystem when dealing with a malicious HCI TTY Bluetooth device.

Affected Systems and Versions

All Linux kernel versions starting from 3.13 are susceptible to this vulnerability, emphasizing the widespread impact across various Linux distributions.

Exploitation Mechanism

An attacker with local access to the system can exploit the vulnerability by attaching a specially crafted malicious HCI TTY Bluetooth device, leading to a double-free memory corruption and subsequent system crash.

Mitigation and Prevention

This section outlines immediate steps to take and long-term security practices to enhance system resilience against CVE-2021-3564.

Immediate Steps to Take

System administrators are advised to apply security updates promptly, monitor system logs for unusual activities, and restrict physical access to vulnerable systems.

Long-Term Security Practices

Implementing the principle of least privilege, regularly updating system software, and conducting security audits can help in preventing similar vulnerabilities in the future.

Patching and Updates

Vendors like Red Hat and Debian have released security updates to address CVE-2021-3564. It is crucial for users to apply these patches immediately to mitigate the associated risks.