What are malicious browser extensions and how do they steal data?

Malicious extensions disguise themselves as useful browser plugins, such as ad blockers, translators, or visual themes. Once installed, they receive broad permissions to read and modify the content of all web pages visited by the user, opening up vast opportunities for cybercriminals.

The main threat of such add-ons lies in the interception of confidential data. An extension can track entered credentials on banking and social media sites, substitute cryptocurrency wallet numbers in the clipboard, or inject malicious ads directly into the body of displayed websites.

To protect yourself, you should install add-ons only from official developer stores and carefully review the permissions they request. If an extension requires access to all sites without an obvious reason, it is better to refuse its installation, and existing plugins should be regularly audited and unused ones removed.