4ndr0serviceguard

A dual-purpose Chrome Extension:

• For everyday users: proactively disable Service Workers to improve browser performance, reduce tracking, and gain predictability.
• For Red Team operators and penetration testers: a tactical tool to neutralize client-side Service Worker defenses and expose hidden application logic.

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The Problem

Service Workers enable offline caching, push notifications, background sync, and request interception. While useful, they can lead to:

• Stale Content: Aggressive caching hides fresh content.
• Unwanted Notifications: Persistent prompts and background messages.
• Performance Overhead: Extra CPU and battery usage.
• Privacy Concerns: Silent background requests without user control.
• Security Barriers: Obfuscation of backend APIs and enforced client-side validation.

For power users, developers, and security professionals, controlling this layer is essential.

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The Solution: The Nullifier Protocol

4ndr0serviceguard enforces a default-deny Service Worker policy, blocking all registrations globally unless explicitly allowed.

• Everyday users get faster, cleaner, and more private browsing.
• Operators can surgically dismantle Service Worker protections, revealing hidden endpoints, bypassing client-side validation, and triggering legacy fallbacks.

This model delivers predictability, privacy, and expanded attack surface visibility.

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Features

• 🛡️ Nullifier Protocol: Global kill switch for Service Workers.
• ✍️ Intelligent Whitelist: Add trusted domains and their subdomains (e.g., google.com covers docs.google.com).
• 🤫 Stealth API Nullification: Returns fake registration promises to avoid breakage or detection.
• ⚡ Instant Execution: Injected at document_start before page scripts.
• ✅ Live Validation: Input checked in real time via popup.
• ✨ Manifest V3: Modern, asynchronous, and secure codebase.

Additional operator-level traits:

• Surgical Target Enablement: Per-domain SW restoration.
• Zero-Day Race Condition Dominance: Guaranteed execution before target scripts.
• Customizable Source: No build step; edit scripts directly.

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How It Works

Stage 1: Pacification

pacifier.js injects into the MAIN world at document_start. It overwrites navigator.serviceWorker methods with inert stubs. All registration attempts resolve successfully but no Service Worker is active.

Stage 2: Restoration

background.js checks tab URLs against the whitelist. For trusted domains, it reinjects original API methods with chrome.scripting.executeScript, restoring Service Worker functionality.

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Red Team Operational Scenarios

1. Bypassing Client-Side Validation & Controls

• Target: secure-bank.com uses SW to add tokens or encrypt payloads.
• Action: Do not whitelist. SW is nullified.
• Result: Intercept proxy sees raw API traffic. Test injection, tampering, bypasses.

2. De-cloaking Hidden Endpoints

• Target: content-delivery.net proxies all API calls through SW.
• Action: Disable SW.
• Result: App falls back to direct requests, exposing real backend URLs.

3. Forcing Legacy Fallback Modes

• Target: shiny-app.io with complex PWA logic.
• Action: Nullify SW.
• Result: Legacy app path loads. Older vulnerabilities may be exposed.

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Installation

Not on Chrome Web Store. Load manually:

git clone https://github.com/4ndr0666/4ndr0serviceguard.git

1. Go to chrome://extensions.
2. Enable Developer mode.
3. Click Load unpacked and select the repo folder.
4. Extension icon appears in toolbar.

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Usage

Click the icon to open control popup:

• Nullifier Protocol Switch: Master on/off toggle.
• Whitelist Textarea: Add domains (one per line). Subdomains included automatically. Reload pages after edits.

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Tactical Deployment

• Default-deny applied immediately when extension is loaded.
• Use whitelist to scope Service Worker restoration during active engagements.
• Reload the target tab after whitelist changes.

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Mechanism of Action (MoA)

1. MAIN World Injection: Same privilege as site scripts.
2. API Monkey-Patching: Save and overwrite original navigator.serviceWorker methods.
3. Deceptive Resolution: Return fake ServiceWorkerRegistration objects to avoid detection.
4. Surgical Restoration: Reinstate originals on whitelisted domains.

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Customization

• No build process.
• Modify JS source directly to fit engagement needs.
• Reload via chrome://extensions after editing.

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Contributing

PRs and issues are welcome. Bug fixes, new features, and operational improvements encouraged.

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License

Licensed under the MIT License. See LICENSE.