Background

2021 I started working in cybersecurity, focusing on infrastructure security and offensive security research. As part of my role, I reviewed the security posture of various tools and platforms my company used.

Browser extensions became a focus area. Extensions request specific permissions during installation, but most users don't understand what those permissions actually allow.

A screenshot tool might request access to all your tabs. A productivity extension might want to read your browsing history. The question was: are these permissions necessary for the extension to function, or is it requesting excessive access?

Understanding Extension Permissions

Extensions declare their required permissions in their manifest file. Common permissions include tabs (access to tab information), cookies (read/write cookies), history (browsing history), webRequest (monitor network traffic), and host permissions like <all_urls> (access to all websites).

The issue isn't the permissions themselves. They're documented and intentional. The issue is transparency. Users click "Add to Chrome" without understanding what they're granting access to.

An extension with tabs + history + <all_urls> can track every website you visit. An extension with webRequest + cookies can intercept session tokens. These aren't vulnerabilities, they're features that users unknowingly approve.

Building a Security Strategy

At my company, I built an extension security review process. This involved analyzing manifest files, evaluating permission requests against functionality requirements, and identifying extensions with excessive access.

I developed a weighted scoring system that considers both individual permissions and dangerous combinations. For example, clipboardRead alone is medium risk. But clipboardRead + nativeMessaging creates a credential exfiltration path.

This hands-on work gave me a clear understanding of what separates legitimate tools (ad blockers, password managers) from extensions requesting unnecessary access.

Existing Tools

I looked at existing extension analysis tools: CRXcavator, ChromeStats, and SpinAI. They had limitations.

CRXcavator shut down. ChromeStats provided scores but lacked real-time analysis of installed extensions. SpinAI had accuracy issues and didn't show a live view of what's currently installed on your browser.

What I needed was simple: a tool that analyzes the extensions I actually have installed, shows me their permission footprint, and lets me disable risky ones immediately.

That didn't exist, so I built it.

How Browse Smarter Works

Browse Smarter uses the Chrome Management API to enumerate installed extensions and read their declared permissions. It applies a scoring algorithm that evaluates:

1. Individual permission risk (weighted by severity: critical permissions like webRequestBlocking score higher than low-risk permissions like activeTab)

2. Host permission scope (<all_urls> is riskier than specific domain access)

3. Dangerous permission combinations (10 specific combos that indicate surveillance, data exfiltration, or traffic interception capabilities)

The result is a 0-100 safety score where higher is safer. Extensions are categorized as Low Risk (81-100), Medium Risk (51-80), High Risk (21-50), or Critical Risk (0-20).

All analysis happens locally in your browser. The extension reads permission data from installed extensions but doesn't transmit anything externally.

Goal: Transparency

The goal isn't to scare people away from extensions. Many extensions need significant permissions to function properly. Ad blockers need webRequest + <all_urls> to block ads. Password managers need access to form fields.

The goal is transparency. Users should understand what they're granting access to. An extension requesting tabs + history + <all_urls> might be legitimate, but you should know it can track your browsing.

Browse Smarter makes that visible. You see the score, you see the permissions, you decide whether the functionality is worth the access being requested.

What's Next

The current version (v1.0) uses permission-based scoring. Future versions will add behavior monitoring to detect extensions that make excessive network requests or contact suspicious domains.

I'll document the methodology, share research on extension security patterns, and update the scoring algorithm as new permission types and attack vectors emerge.

The extension is free and will stay free. The code is straightforward enough that anyone with security experience can verify what it's doing.