Chrome vs Firefox Extensions: Security Risks

TL;DR

Firefox generally offers more user control and a stricter review process for extensions compared to Chrome, making it potentially safer. However, both browsers can be vulnerable. This guide explains why, and how to mitigate risks in either browser.

Why Firefox Extensions Are Often Considered Safer

1. Extension Manifest V3 (MV3) & Google’s Control: Chrome moved to MV3 which significantly restricts what extensions can do. While intended for security, it also gives Google more control over extension functionality and approval. This centralisation is a concern for some.
   • MV3 limitations mean some privacy-focused extensions struggle to function.
   • Google has the power to unilaterally remove or alter extensions.
2. Firefox’s Add-on Review Process: Firefox has a more community-driven and transparent review process.
   • Extensions are reviewed by Mozilla staff *and* a community of volunteers.
   • Greater emphasis on source code audits.
   • More readily accepts extensions with self-hosting options, increasing trust for some users.
3. User Control & Permissions: Firefox provides more granular control over extension permissions.
   • Easier to see exactly what each extension can access and modify.
   • More straightforward process for disabling specific permissions.
4. Extension Signing: Both browsers use extension signing, but Firefox’s approach is often seen as more robust.
   • Firefox requires extensions to be signed by a trusted entity (Mozilla or verified developers).
   • This makes it harder for malicious actors to distribute fake or compromised extensions.

Why Chrome Extensions Can Be Riskier

1. Larger Target: Chrome has a much larger user base, making it a more attractive target for attackers.
   • More extensions available = higher chance of malicious software slipping through.
2. Web Store Security Issues: The Chrome Web Store has historically had issues with malicious extensions being published.
   • Fake or cloned extensions are common, often designed to steal data or inject ads.
   • Google’s automated review process isn’t always effective at catching these threats.
3. MV3 Concerns: As mentioned above, the move to MV3 has created new security challenges.
   • Some legitimate extensions have been removed due to compliance issues.
   • The restrictions can make it harder for developers to maintain privacy features.

Mitigating Risks in Both Browsers

1. Install Only Trusted Extensions: This is the most important step.
   • Research the developer and extension before installing.
   • Check reviews and ratings carefully.
   • Avoid extensions with vague descriptions or excessive permissions requests.
2. Review Extension Permissions: Regularly check what permissions your extensions have.
   • Chrome: Type chrome://extensions in the address bar and expand ‘Details’ for each extension.
   • Firefox: Type about:addons in the address bar, select Extensions, then click ‘Manage Extension Permissions’.
3. Keep Your Browser Updated: Updates often include security fixes.
   • Enable automatic updates.
4. Use a Cybersecurity Tool: Consider using an antivirus or anti-malware program with browser extension protection.
5. Regularly Audit Extensions: Periodically review the extensions you have installed and remove any that are no longer needed.

Conclusion

While Firefox generally offers a slightly more secure environment for extensions, both browsers require vigilance. By following these steps, you can significantly reduce your risk of installing malicious software.