CVE-2018-18203 : Security Advisory and Response

Subaru StarLink Harman head units from 2017 to 2019 are vulnerable to a firmware alteration attack via USB ports.

Understanding CVE-2018-18203

The vulnerability in the update mechanism of Subaru StarLink Harman head units allows attackers to modify the firmware through USB ports.

What is CVE-2018-18203?

The vulnerability enables attackers with physical access to the vehicle's USB ports to change the head unit's firmware by exploiting a bug in the update mechanism.

The Impact of CVE-2018-18203

Attackers can install malicious firmware on the head unit, persist even after updates, and execute unauthorized code with root user privileges.

Technical Details of CVE-2018-18203

The technical aspects of the vulnerability are as follows:

Vulnerability Description

The flaw allows the acceptance of altered QNX6 filesystem images, bypassing validity checks.

Affected Systems and Versions

Subaru StarLink Harman head units from 2017 to 2019.

Exploitation Mechanism

Attackers need physical access to the vehicle's USB ports and specific Harman encryption/decryption code to exploit the vulnerability.

Mitigation and Prevention

Protecting against CVE-2018-18203 involves taking immediate and long-term security measures:

Immediate Steps to Take

Avoid connecting untrusted devices to the head unit's USB ports.
Regularly update the head unit firmware with verified patches.

Long-Term Security Practices

Implement secure boot mechanisms to prevent unauthorized firmware changes.
Conduct regular security audits and penetration testing to identify vulnerabilities.

Patching and Updates

Install firmware updates provided by Subaru to address the vulnerability.