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An open-source, Manifest V3 browser extension for detecting phishing attacks that impersonate Microsoft 365 sign-in pages.

Install it from the Chrome Store here or the Edge store here.

Firefox Support: The extension also works on Firefox 109+. See Firefox Support for installation instructions.

Features

• Detection engine – loads rules from rules/detection-rules.json and analyses URLs and page content to block or warn about suspicious sites targeting Microsoft 365 credentials
• Configuration management – merges local settings, branding, and browser policies provided through Chrome managed storage (GPO/Intune)
• Policy enforcement & logging – loads enterprise policies, tracks compliance mode, and records audit events for security reporting
• Custom branding – logos, colors, and messaging are defined in config/branding.json and can be replaced for white‑label deployments
• Options & popup interfaces – interactive pages (options/, popup/) let administrators adjust settings and view detection status

Requirements

• Chrome 88+, Edge 88+, or Firefox 109+ (browsers supporting Manifest V3)
• Optional enterprise management via Group Policy or Microsoft Intune for policy enforcement

Installation

Manual

Chrome/Edge

1. Clone this repository.
2. In Chrome/Edge open chrome://extensions/ or edge://extensions and enable Developer mode.
3. Click Load unpacked and select the project directory.
4. Verify the extension using test-extension-loading.html.

Firefox

1. Clone this repository.
2. Run npm run build:firefox to configure for Firefox.
3. Open about:debugging#/runtime/this-firefox in Firefox.
4. Click Load Temporary Add-on and select manifest.json.
5. For more details, see Firefox Support.

Enterprise

Package the extension directory (zip) and deploy through your browser’s policy mechanism. Managed settings follow the schema in config/managed_schema.json.

Configuration

• Policies – see config/managed_schema.json for available options such as URL blocking, logging, and performance controls.
• Branding – update config/branding.json to change names, logos, and colors.
• Detection rules – edit rules/detection-rules.json or enable remote rules using the detectionRules section in the policy schema.

Contributing

See CONTRIBUTING.md for guidelines. The project uses plain JavaScript modules and does not include a build system; package the directory directly for distribution.

License

Licensed under the AGPL-3.0. See LICENSE for details.