The Hardware Exploit Vector
Google Chrome supports an advanced API known as Web Serial. This API allows web applications (like embedded systems programmers or specialized medical dashboards) to bypass standard operating system drivers and communicate directly with physical Serial ports (COM ports) plugged into your motherboard. While incredible for electrical engineers, it is a significant security vulnerability for the average user. Malicious websites can exploit this direct bridge to silently probe your computer for vulnerable legacy hardware or attempt to execute unencrypted firmware commands via the serial protocol. You must paralyze this API.
How to Block Serial Port Access Globally
You can permanently sever the browser’s ability to interface with your physical motherboard ports via Chrome’s Site Settings.
- Open the Google Chrome desktop browser.
- Click the three vertical dots (â‹®) in the top right corner and select Settings.
- In the left-hand sidebar, click on Privacy and security.
- In the main window, click on Site settings.
- Scroll down to the “Permissions” heading and click to expand Additional permissions.
- Click on Serial ports.
- Under the “Default behavior” heading, select the radio button for “Don’t allow sites to connect to serial ports.”
Total Physical Isolation
The change takes effect instantly. Google Chrome will completely sever its internal connection to your operating system’s raw serial driver stack. The browser is now permanently blind to any COM ports or legacy hardware physically wired to your machine. If a website attempts to execute a Web Serial script to scan your ports, the API call will instantly auto-reject in the background, returning a null value. This guarantees absolute physical isolation between unverified web code and the vulnerable hardware peripherals attached to your computer.