Understanding Browser Extension Management

Organizations typically have limited visibility into what browser extensions employees install. Unlike traditional applications that go through software distribution channels, browser extensions are installed directly by end users from browser-specific web stores, often without any approval process. This creates several challenges:

  • Shadow IT - Users install extensions that IT has no knowledge of, creating blind spots in the security posture.

  • Data leakage - Extensions with broad permissions can read data from any page a user visits, including internal applications, email, and financial systems.

  • Supply chain risk - Legitimate extensions can be sold to new owners or compromised through developer account takeovers, silently turning trusted extensions into malware delivery vehicles.

  • Compliance - Regulatory frameworks increasingly require organizations to demonstrate control over software running on endpoints, including browser extensions.

The Discover, Review, Enforce Workflow

Browser extension management follows a three-phase workflow:

Phase 1 - Discover

The first step is gaining visibility. Create a Browser Extension Inventory Policy and target it to one or more computer groups. Once deployed, the Privilege Manager agent on each endpoint scans browser profiles for all local users and reports every installed extension back to the server.

Results appear in the Browser Extension Inventory reports, giving you a fleet-wide picture of what extensions are in use. Refer to Enabling Extension Inventory for detailed setup instructions.

Phase 2 - Review

With inventory data flowing in, use the reports and extension detail views to evaluate what has been discovered. Privilege Manager provides risk scores, AI-powered classification, and permission analysis to help you prioritize which extensions require attention.

The Browser Extension Inventory report surfaces the highest-risk extensions first, and the Extension Resource Detail view lets you inspect an individual extension's permissions, version history, and installation footprint across your environment.

Phase 3 - Enforce

After reviewing the inventory, create enforcement policies that define which extensions are allowed and which are blocked. Privilege Manager supports two enforcement modes:

  • Allow List mode - Only explicitly approved extensions may be installed. All other extensions are blocked.

  • Deny List mode - All extensions are permitted except those explicitly blocked.

Refer to Building Enforcement Policies for instructions on creating and deploying enforcement policies.

How Extensions Are Identified

Each browser extension is uniquely identified in Privilege Manager by a composite resource key of (Source, Browser, StoreId). Every unique combination of these three values is a separate extension resource.

  • Source - The extension store the extension was published to: Chrome, Edge, Firefox, or Unknown. The agent derives Source by matching the extension's manifest update_url against the known store update endpoints (for example, clients2.google.com: Chrome Web Store, edge.microsoft.com: Edge Add-ons, addons.mozilla.org: Firefox AMO). An extension sideloaded from a local file or served from a custom update server resolves to Unknown.

  • Browser - The browser the extension was discovered running in (Chrome, Edge, or Firefox) and Source are not always the same: a Chrome Web Store extension that a user has installed into Microsoft Edge has Source = Chrome and Browser = Edge.

  • StoreId - The manifest ID string assigned by the store (for example, cjpalhdlnbpafiamejdnhcphjbkeiagm for uBlock Origin from the Chrome Web Store, or uBlock0@raymondhill.net for uBlock Origin from Firefox AMO).

Because each store issues its own StoreId, the same extension published to multiple stores appears as multiple resources. Extension resource names use a browser-suffix format to make the distinction unambiguous in the UI:

  • uBlock Origin (Chrome) - The Chrome Web Store variant

  • uBlock Origin (Firefox) - The Firefox Add-ons variant

  • uBlock Origin (Edge) - The Edge Add-ons variant

This naming convention appears throughout the inventory reports and detail views. The raw manifest name (without the browser suffix) is also available in report columns and the extension detail view for cases where you need to match the same extension across stores.

Because StoreIds differ across stores, an Allow List or Deny List entry for a Chrome Web Store extension does not automatically apply to the same extension in the Firefox or Edge stores. You must add each store variant you want to control as a separate entry.

Allow List and Deny List Modes

Enforcement policies operate in one of two modes:

  • Allow List mode is the most restrictive approach. When an Allow List policy is active, only extensions that appear on the approved list are permitted. Any extension not on the list is blocked. This mode is appropriate for high-security environments where administrators want tight control over what runs in the browser.

  • Deny List mode is a more permissive approach. All extensions are allowed by default, and only extensions explicitly added to the list are blocked. This mode is appropriate for organizations that want to remove known-bad extensions without restricting users from installing other extensions.

What Happens When an Extension Is Blocked

When Privilege Manager blocks a browser extension, the extension is uninstalled from the browser via the browser's native policy mechanism. The extension is not merely disabled; it is fully removed. The browser's built-in enterprise policy engine handles the removal, which means:

  • The extension's code and data are deleted from the browser profile.

  • The user cannot reinstall the extension while the enforcement policy is active.

  • The browser displays a notification or visual indicator that the extension was removed by enterprise policy (the exact presentation varies by browser).

Enforcement relies on browser policy support. The Privilege Manager agent writes policy entries that the browser reads on startup or at its next policy refresh interval. There may be a brief delay between policy deployment and the browser acting on the policy.