How to check if you've been the victim of a breach like the Yahoo hack

In what has already been called the worst hack ever, Yahoo confirmed Thursday that at least 500 million users were affected by a security breach from a state-sponsored actor. 

If you want to tighten up your security, one of the first steps you should take is checking to see how many of your accounts have already been impacted by a security breach. 

While the Yahoo hack is the biggest, there have been plenty of other massive data breaches over the years and chances are you've been affected by at least a few of them. It's true that most companies try to alert their users to these breaches as soon as possible, but even they sometimes don't find out about them until months or years after the fact.  Read more...