A browser extension can operate inside the same browser that employees use for customer records, invoices, and administration. Depending on its permissions, it may read page content, inject scripts, or interact with browsing activity. The extension can therefore become part of a business application's data path without appearing in that application's integration settings.
An access inventory that covers only connected SaaS accounts can miss this endpoint-level relationship. The review needs to include what the browser has authorized the extension to do.
Permissions describe capabilities, not observed behavior
Chrome documents the permissions available to extensions and the warnings associated with them. Host permissions and API permissions have different effects, and some capabilities depend on their combination. Chrome's permission reference describes the platform's controls.
An illustrative sales extension reads selected CRM pages to format notes. Access limited to that CRM has a different scope from permission to read and change content across all visited sites. Neither permission set, by itself, establishes whether the extension actually transmits customer information; that requires further evidence.
Record the publisher and business purpose
Inventory the extension identifier, publisher, installed version, requested permissions, deployment method, and responsible business owner. Identify whether installation is centrally managed or left to individual users. A product name alone may not distinguish similarly named extensions.
Review how updates are delivered and how permission changes are handled by the browser and organizational policy. The team needs a way to connect a changed capability or publisher relationship to the affected employee population.
Use a synthetic business session for review
Create a browser profile with test accounts and synthetic records. Exercise the extension's intended feature, then inspect the documented and observed data flow using approved tools. Keep real customer sessions and credentials outside the test environment.
Compare the requested access with the function the business approved. If the extension needs broader access for a documented reason, record that reason and the accepted scope. If the scope cannot be explained, the review has identified a question requiring resolution rather than proof of malicious behavior.
Verify removal and incident visibility
Test whether an administrator can identify affected installations and remove or disable the extension through the supported management process. Record which devices are outside management and what evidence is available about prior versions or use.
Removing an extension prevents its future browser execution in the managed context, but it does not recover information already transmitted. Incident response therefore needs both endpoint action and a review of the extension's accessible data during the relevant period.
The resulting inventory can sit alongside SaaS integrations and service accounts. Each entry describes a business purpose, technical authority, owner, and removal path, giving the organization a more complete view of the software that can encounter its browser-based information.
Sources
OWASP: Browser Extension Vulnerabilities. The sales extension is illustrative.
