If you've seen a warning message or a popup online telling you that you've been hacked and that you need to take immediate action, chances are good that it's just a scam. These are nothing more than scare tactics designed to make you fall for something, whether it be giving your information or actually making a payment. But with all of the major security breaches happening, like the one at Marriott, there is some legitimate concern that your accounts could have been compromised. In other words, there is a chance you've been "pwned."
There's a quick and easy way to find out if you're a victim: haveibeenpwned.com. Just enter the email address of the account that you want to check, and this site will help you assess where your personal data has been exposed. It provides information about the breaches that your account was subject to, and what details were leaked. This way, you can change passwords and take the necessary steps to secure that account.