Whether you want to block ads, keep a to-do list or check your spelling, browser extensions allow you to do all of the above and more, improving convenience, productivity and efficiency for free, which is why they are so popular. Chrome, Safari, Mozilla — these and many other major Web browsers — have their own online stores to distribute thousands of extensions, and the most popular plug-ins there reach over 10 million users. However, extensions are not always as secure as you might think — even innocent-looking adds-on can be a real risk.
First of all, not every innocent-looking extension is, in fact, innocent. Malicious and unwanted add-ons promote themselves as useful, and often do have legitimate functions implemented along with illegitimate ones. Some of them may even impersonate a popular legitimate extension, their developers going so far as to stuff keywords so that their extension appears near the top of the browser’s extension store.