Lists of millions of compromised user accounts have surfaced on the Internet. Some research institutes have prepared this data and offer ways to check whether you are affected.
Here is the link to test your own email(s) at the Hasso Plattner Institute in Potsdam to see if you are affected:
You enter your e-mail address there and in a few minutes you get a result sent to your e-mail box, whether your own data appears in these directories of the web criminals.
There’s also a answer to common questions and a explanation of the reply emails and what they say.
If your own e-mail address appears in the list, this does not necessarily mean that the problem still exists, since you could theoretically have changed all the access data that were created with this e-mail in the meantime. You shouldn’t count on it.
If your email is on the list, as a precaution, we recommend that you change the password for all user accounts on websites that use this email address as your identification.