Secure Your Browser Extensions Before Attackers Exploit Them
Comprehensive security testing for browser extensions - permission analysis, content script injection, data exfiltration testing, CSP bypass assessment, cross-origin request abuse, and malicious update detection - ensuring your extensions are safe for millions of users.
Why Web Extensions Security Matters Now
The threat landscape is evolving rapidly. These are the risks your organization faces without proper web extensions security measures.
Excessive Permission Abuse
Browser extensions requesting broad permissions (tabs, webRequest, cookies, storage) can access everything a user sees online.
Supply Chain Attacks
Extension marketplace takeovers - buying legitimate extensions, injecting malicious code via updates, and exploiting auto-updates.
Data Exfiltration
Extensions can silently exfiltrate browsing data, form inputs, session tokens, and credentials to remote servers via content scripts.
Enterprise Browser Risks
Vulnerable internal extensions provide attackers with persistent access to the corporate browsing environment across all employee browsers.
What We Cover
Comprehensive coverage across all critical areas of web extensions security.
Proven Web Extensions Security Methodology
A systematic, repeatable methodology refined over 4,800+ security assessments across 24+ countries.
01 Manifest & Permission Review
Analyze extension manifest for overprivileged permissions, unsafe CSP directives, and configuration weaknesses that expand the attack surface beyond operational necessity.
02 Static Code Analysis
Review content scripts, background scripts, and popup code for XSS, injection flaws, insecure API usage, and data handling vulnerabilities.
03 Dynamic Runtime Testing
Install and test the extension in instrumented browsers, monitoring network requests, storage access, DOM modifications, and inter-process communication.
04 Data Flow Analysis
Trace how the extension collects, processes, stores, and transmits user data — identifying exfiltration risks, insecure storage, and privacy violations.
05 Attack Simulation
Attempt to exploit identified vulnerabilities including CSP bypass, content script injection, message passing abuse, and update mechanism hijacking.
06 Compliance & Hardening
Verify compliance with Chrome Web Store and Firefox AMO security policies, and provide hardening recommendations for Manifest V3 migration.
What Sets Our Web Extensions Security Apart
Manifest V3 Expertise
Deep expertise in the latest Chrome Manifest V3 extension platform - service workers, declarativeNetRequest, and the new permission model.
Cross-Browser Testing
Testing across Chrome, Firefox, Edge, and Safari extension platforms - each has unique security models and vulnerability patterns.
Automated + Manual Analysis
Automated scanning for known vulnerability patterns combined with manual expert review for logic flaws, design issues, and subtle data leaks.
Enterprise Extension Audit
Specialized assessment of enterprise-deployed extensions, group policy configurations, and managed browser extension inventories.
Update Security Verification
Test the extension update pipeline for supply chain risks - man-in-the-middle opportunities, unsigned updates, and compromised distribution channels.
Store Compliance Pre-Check
Pre-submission compliance verification against Chrome Web Store and Firefox AMO policies - avoiding rejection and ensuring quick approval.
What You Receive
Comprehensive documentation that drives action, not just awareness.
Extension Security Assessment Report
Permission Analysis & Minimization Guide
Vulnerability Findings with PoC Exploits
Data Flow & Privacy Risk Analysis
Manifest Hardening Recommendations
Store Compliance Pre-Check Report
Remediation Priority Matrix
Re-Testing Verification Report
Why Trust Us with Your Web Extensions Security
Domain-specific expertise that sets us apart in web extensions security.
Browser Security Specialists
Dedicated browser security researchers who have disclosed vulnerabilities in popular extensions and understand the unique attack surface of browser extension platforms.
Manifest V3 Migration Support
Expert guidance on migrating from Manifest V2 to V3 while maintaining functionality - navigating the security improvements and API changes.
Real Attack Techniques
We test using techniques actually used by malicious extensions in the wild - content script injection, clickjacking, token theft, and silent data exfiltration.
Enterprise & Consumer Coverage
Assessment capabilities for both consumer marketplace extensions and enterprise-deployed internal extensions with unique deployment and policy requirements.
Standards & Frameworks We Align With
Secure Your Browser Extensions
A 30-minute scoping call costs nothing and could prevent your next breach. Talk to our CREST-certified specialists today.
Or email us at contact@briskinfosec.com
Web Extensions Security FAQs
Common questions about our Web Extensions Security Assessment service and testing methodology.
What browsers do you test extensions for?
We test extensions for Chrome (Manifest V2 & V3), Firefox (WebExtensions), Microsoft Edge (Chromium-based), and Safari (Web Extensions). Each platform has unique security models that require specific testing approaches.
Can you test enterprise-deployed extensions?
Yes. We assess internally developed extensions deployed via Google Admin Console, Microsoft Intune, or Group Policy - including managed browser profiles, policy configurations, and force-installed extension security.
Do you test for data privacy violations?
Absolutely. Our assessment includes complete data flow analysis - tracking what user data the extension collects, how it's stored, where it's transmitted, and whether data handling complies with GDPR, DPDPA, and store privacy requirements.
Can you help with Manifest V3 migration?
Yes. We provide both security assessment and migration consulting - helping your team move from Manifest V2 to V3 while resolving security issues and adapting to the new service worker model, declarativeNetRequest API, and restricted permissions.
Secure Your Extensions
From permission analysis to supply chain risk — our CREST-certified team delivers comprehensive browser extension security assessments trusted by enterprises worldwide.
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