The Lagoon TechMy little blog in Cyberspace.

Many people use web browser add-ons (such as Ad-blockers) for their everyday browsing. What most people are unaware of is that many of these add-ons have permissions that allow the add-on to view the content of the web pages the user is viewing.

The problem? If someone has installed a malicious add-on, their web browsing data (e.g., browsing history, password credentials, what they type into a website, etc.) would have been sent to the add-on’s creator. Now I am not implying that every single web browser add-on does this, but there is a very high potential that this can happen.

Would only using open-source browser add-ons be a safe option? Well open-source add-ons would definitely lower the chance that someone would get away with spying on you. However open-source projects do not have a spotless security track record either. There is still some risk.

Even Mozilla themselves warn about this problem with web browser add-ons (also called extensions).

Here is an example of what I am talking about (https://www.zdnet.com/article/mozilla-removes-avast-and-avg-extensions-from-add-on-portal-over-snooping-claims/).