Web browsing can be a game of functionality and convenience, largely thanks to browser extensions. These software components, designed to customize and enhance your online experience, have become universal. They block ads, manage downloads, check grammar, and much more.

Browser extensions are generally safe, but there can be cybersecurity threats associated with them. We’ll guide you through the safe use of browser extensions and provide practical advice to ensure your online browsing remains secure and convenient.

What are browser extensions?

Browser extensions are software modules designed to enhance your web browsing experience. They’re also referred to as add-ons or plugins, as they integrate with your browser. Extensions provide functionality that isn’t included within the base browser package, add new features, and more. You can think of them as upgrades or customization tools for your browser, similar to how apps add functionality to your smartphone.

Some popular types of browser extensions include ad blockers, virtual private networks (VPNs), password managers, and download managers. These extensions are typically available on a variety of browsers, such as Google Chrome, Mozilla Firefox, Safari, and Microsoft Edge. Depending on your preferred browser, you can find extensions through its respective official web extension store.

Are browser extensions safe?

The answer isn't as straightforward as it might seem. Yes, many extensions are designed to be safe and beneficial. However, it's also possible to encounter extensions that can be harmful. The primary concern with browser extensions is that you are essentially introducing new software to your device. This software, though intended to augment your browsing experience, could potentially open up avenues for threats.

Browser extensions can present security risks if they contain hidden malware or security flaws. For instance, a compromised extension might be able to read your data, alter web content, or even insert malicious scripts into visited websites. Moreover, the privacy risks cannot be overlooked. Some extensions might track your browsing history, collect your personal information, and even sell this data to third-party advertisers. If this user data gets into the wrong hands, it can be used for phishing attempts, identity theft, and unwanted targeted advertising.

6 browser extension red flags

While browser extensions can enhance your online experience, it's essential to be aware of potential red flags during your extension download process:

1. Source of the extension: Always download extensions from the official web stores, such as the Chrome Web Store, Firefox Add-ons, Safari Extensions, or Microsoft Edge Add-ons. Extensions from third-party sites or direct links should be considered suspicious.
2. Permissions requested: When you install an extension, it will ask for certain permissions. Be cautious if an extension is asking for access that seems unrelated to its functionality. For example, a weather extension probably doesn't need access to your email.
3. Developer reputation: Before downloading, check the reputation of the developer. Look for their other extensions and how they are rated and reviewed.
4. Extension reviews and ratings: Just like any product, you should read through the reviews and ratings. An extension with negative reviews or low ratings might be a red flag.
5. The number of users: If an extension has been available for a long time but has a low number of users, this might be a clear indication that something isn’t quite right.
6. Extension update frequency: If an extension hasn't been updated for a long time, it could imply that the developer has stopped supporting it. Such extensions can become security liabilities over time.

By staying alert and following the recommended practices, you can enjoy the benefits of browser extensions while minimizing their potential risks.

How to check for malicious browser extensions

Let's start on a positive note — even if you've accidentally downloaded a malicious browser extension, the damage isn't irreversible. You can safeguard your digital ecosystem by taking preventative measures. Here are step-by-step guides on how to recognize and remove potentially harmful browser extensions across various web browsers.

How to check for malicious extensions on Google Chrome:

1. Open Chrome.
2. Click on the three-dot menu in the top-right corner.
3. From this dropdown, select Extensions, then Manage extensions.
4. You will now see a list of all the installed extensions.
5. Review your extensions. If you find any extension that you did not install or recognize, it might be malicious.
6. Click the Remove button to uninstall it.
7. After removing the extensions, it's a good practice to change your privacy settings and clear the browser cache. To do this, navigate to Settings from the three-dot menu.
8. On the side bar, go to Privacy and security.
9. Select Clear browsing data and check the box for Cached images and files.

How to check for malicious extensions on Mozilla Firefox:

1. Open Firefox.
2. Click on the three-bar menu in the top-right corner.
3. Select Add-ons and themes from the menu.
4. This will open the Add-ons Manager, a tab showing all your installed extensions. Look for any extension you do not recognize, or that seems suspicious.
5. If you find a potentially malicious extension, click on the three-dot menu next to it and select Remove.
6. After removal, clear your browser cache by navigating to Settings.
7. Select the Privacy & Security panel.
8. From the Cookies and Site Data section, click Clear Data.

How to check for malicious extensions on Safari:

1. Open Safari.
2. In the menu bar, go to Safari > Preferences.
3. Click on the Extensions tab to view all installed extensions.
4. If you see any extension that you did not install or that looks suspicious, uncheck the enable box and then click Uninstall.
5. You can empty your cache from Preferences by selecting the Advanced tab.
6. Select the checkbox that reads Show Develop menu in menu bar.
7. Now, you can click the Develop tab from the Safari menu at the top of the page.
8. From the dropdown, select Empty Cache.

How to check for malicious extensions on Microsoft Edge:

1. Open Microsoft Edge.
2. Click on the three-dot menu in the top-right corner.
3. From the dropdown, select Extensions.
4. Once selected, you should see a list of all your installed extensions, or you can click Manage Selections to view them. Look for any extension you did not install or that looks suspicious.
5. If you come across a potentially harmful extension, click on the gear icon next to it and then click “Uninstall.”
6. Then, you can clear your cache by navigating to Settings.
7. Select Privacy, search, and services from the sidebar.
8. Under Clear browsing data, click Choose what to clear.
9. Select Cached images and files from the list.

After removing a malicious extension from any of these browsers, you should also run an antivirus scan to ensure no remnants of malicious extensions remain. We recommend the following antivirus software for their unique scanning capabilities:

• Bitdefender: Directly after installation, Bitdefender prompts you to perform a "one-time scan" of your entire device, which is useful if you are installing antivirus for the first time.
  Get Bitdefender | Read Our Bitdefender Review
• Norton 360: Norton uses artificial intelligence (AI) to analyze all files entering your devices and then blocks anything it flags as suspicious. It also comes with Norton Safe Web, which analyzes the sites you visit to indicate whether a site is safe, potentially unsafe, or not safe at all.
  Get Norton 360 | Read Our Norton 360 Review
• TotalAV: If TotalAV’s system detects anything suspicious, you can quarantine, remove, whitelist, or skip the malicious code.
  Get TotalAV | Read Our TotalAV Review

Remember, keeping your extensions and browsers updated is crucial, as many updates come with improved security measures to keep your browsing experience safe.

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Tips for downloading browser extensions safely

While browser extensions can be beneficial, their safety depends on how you approach them. Here are some cybersecurity tips to keep your browser and data safe:

• Download from official stores: Always download browser extensions from official stores. For instance, Chrome users should visit the Chrome Web Store.
• Check the developer's reputation: Do research on the extension's developer. It’s good news if they have a positive reputation and other highly rated extensions.
• Read user reviews: On that note, reviews and ratings from other users can provide better insights into the extension's performance and any potential issues.
• Keep your browser updated: Always keep your browser up to date. Updates often include security patches that will protect you from possible vulnerabilities that malicious extensions might exploit.
• Check for regular updates: An extension that is frequently updated by the developer is more likely to be safe and secure. A lack of updates can indicate an abandoned extension. This results in potential security liabilities.
• Use reliable antivirus software: Ensure you have reliable antivirus software installed on your device. These programs are designed to detect and prevent threats from malicious extensions. Check out our guide to the best antivirus software for recommendations.
• Limit the number of extensions: You should limit the number of extensions to those you really need and use, as the more you have, the higher the risk.

Browser extension FAQs

Bottom line

Browser extensions can significantly enhance your web experience. But, just as with any software, it comes with potential risks. To stay safe online, ensure you download browser extensions only from trusted sources, keep your browser and antivirus software updated, and routinely check your installed extensions. For more information, check out our guide on the best browser extensions for privacy to keep your internet usage safe and secure.

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Author Details

Ryan L. Clancy

About the Author

Ryan Clancy is a freelance writer and blogger. With 5+ years of mechanical engineering experience, he's passionate about all things engineering and tech. He loves bringing engineering (especially mechanical) down to a level that everyone can understand.