Browser Extension Security: A Practical Guide

TL;DR

Yes, browser extensions can be a big cyber security risk. They have lots of permissions and can see what you’re doing online. But with careful choices and regular checks, you can use them safely.

How Extensions Can Be Risky

Browser extensions are small programs that add features to your web browser (Chrome, Firefox, Edge, etc.). They seem harmless, but they can:

• Track Your Browsing: Some extensions monitor where you go online and what you do.
• Steal Data: Malicious extensions could grab passwords, credit card details, or other personal information.
• Redirect You: They can change the websites you visit, leading to phishing sites.
• Inject Ads: Annoying pop-ups and unwanted advertising are common with bad extensions.

The risk comes from:

• Poorly Written Extensions: Even legitimate extensions can have security flaws.
• Malicious Developers: Some extensions are created specifically to cause harm.
• Extension Takeovers: A good extension might be bought by someone with bad intentions, who then adds malicious code.

How to Stay Safe: Step-by-Step

1. Only Install Extensions You Need: Think carefully before adding anything. Do you really need that extra feature? Fewer extensions = less risk.
2. Check the Developer: Look at who made the extension.
   • Is it a well-known company or individual?
   • Do they have a website and contact information?
   • Search online for reviews of the developer.
3. Read Permissions Carefully: Before installing, look at what the extension is asking to access.
   • “Read and change all your data on websites you visit” is a big red flag unless it’s absolutely necessary for the extension’s function.
   • Understand why an extension needs certain permissions.
4. Look at Reviews & Ratings: Check what other users are saying.
   • Be wary of extensions with very few reviews or lots of negative ones.
   • Fake reviews exist, so look for detailed and genuine feedback.
5. Keep Your Browser Updated: Updates often include security fixes that protect against extension vulnerabilities.
6. Regularly Review Installed Extensions: Take time to go through your extensions list and remove anything you don’t use or trust anymore.
7. Use Built-in Security Features:
   • Chrome Task Manager: Press Shift+Esc while Chrome is open to see which extensions are using the most resources. Suspiciously high usage could indicate a problem.
   • Firefox Add-ons Manager: Go to about:addons in your address bar to manage extensions and check their permissions.
8. Consider Using Extension Security Tools: Some tools can help identify potentially harmful extensions. Examples include:
   • WOT (Web of Trust): A browser add-on that provides reputation ratings for websites and extensions.
   • Extension Monitor: Checks extensions for privacy issues.

Checking Extension Permissions (Example – Chrome)

1. Type chrome://extensions into your address bar.

2. Find the extension you want to check.

3. Click “Details”.

4. Scroll down to see the “Permissions” section. Review these carefully!

Removing Suspicious Extensions

1. Chrome: Type chrome://extensions into your address bar, find the extension and click “Remove”.
2. Firefox: Go to about:addons in your address bar, find the extension and click “Remove”.
3. Edge: Type edge://extensions/ into your address bar, find the extension and click “Remove”.