# Malicious Browser Extensions: Permissions to Review Before Installing > An extension can read pages, change searches or capture data depending on its permissions. Use this checklist before installing or keeping one. - Canonical article: [https://www.metacyber.guru/articles/malicious-browser-extensions](https://www.metacyber.guru/articles/malicious-browser-extensions) - Category: Browser Privacy - Author: Muhammad Azhar - Published: August 14, 2026 - Last reviewed: 2026-08-14 A browser extension runs close to the pages you open. Permission to “read and change data on all websites” may be necessary for a password manager, but it is excessive for a simple calculator. ## Before installing - Confirm the publisher and official project site. - Read the exact permission request. - Check recent reviews for ownership or behavior changes. - Prefer one maintained extension over several overlapping tools. ## After an update Extensions can change owners or request new access. Treat a sudden permission expansion as a fresh installation decision. Remove abandoned tools rather than leaving them disabled indefinitely. ## Warning signs Changed search results, new tabs, injected ads, unexpected login pages and high browser resource use deserve investigation. Remove the extension, reset altered settings and change credentials if sensitive pages may have been observed. Extensions are software. Apply the same standard you would use before installing a desktop application: clear purpose, accountable publisher, minimal access and ongoing maintenance. ## Site access can often be narrowed Some browsers let an extension run only when clicked or only on selected sites. Use that control when permanent access is unnecessary. A coupon extension does not need to inspect webmail, and a meeting tool does not need every shopping page. ## Enterprise review Organizations should maintain an allowlist for high-risk roles, record extension identifiers and monitor ownership changes. Removing local installation rights without supplying approved alternatives often drives users toward worse workarounds. ## Updates can change a previously safe extension An abandoned add-on may be sold, compromised or updated with broader permissions. Review recent ownership, permission changes, release notes and user reports. A sudden request to read every website after years of limited access deserves investigation, even if the store listing still looks familiar. ## Respond to suspected extension theft Remove the extension, restart the browser and review synced devices because synchronization can reinstall it elsewhere. Change passwords and revoke sessions for accounts used while the extension had page access, prioritizing email and finance. Check whether search settings, startup pages or policies were modified. Install the smallest number needed, prefer tools from accountable publishers and grant site access only where the feature operates. Store approval is a useful screen, not a guarantee. ## Sources and further reading - [Google Chrome Help: Install and manage extensions](https://support.google.com/chrome_webstore/answer/2664769) - [CISA: Securing web browsers](https://www.cisa.gov/sites/default/files/2023-09/CISA%20CEG%20Securing%20Web%20Browsers%20And%20Defending%20Against%20Malvertising.pdf) --- This Markdown edition is provided for language-model retrieval. The canonical human-readable page is the HTML article linked above.