An extension (browser add-on) is a light program that works inside the browser and changes its behaviour. It is installed from the browser's official store and usually has an icon next to the address bar.

Common uses#

  • Blocking ads.
  • A password manager.
  • Translation or spell checking.
  • SEO and web development tools.
  • Changing the theme or a dark mode.
  • Saving pages or taking notes.

Why should you be careful?#

Extensions often ask permission to "read and change all data on the sites you visit". That means a bad extension can see your passwords, emails and banking information. There have been many cases where a popular extension turned into malware after being sold to someone else.

Safety rules#

  • Install only from the browser's official store.
  • Keep the number low and remove unused ones.
  • Read the requested permissions: are they necessary for its job?
  • Check the developer, the number of users and the reviews.
  • Prefer open-source extensions with a clear track record.

Common mistake#

Installing an extension from a file or a random site to "unlock" something or for a "free download" is the most common route to infection.