2Data Compromised Repository Websites
These sites hold a list of websites that have suffered from a data breach in the past. When a site suffers from a data breach, registered user details especially usernames and passwords usually get revealed to the public. Many people have a bad practice of using the same password for more than one account (e.g., using the same password for Facebook and for an e-mail account), so knowing one password may grant access to other social accounts/services belonging to the same user.
The following sites are popular websites that list information from a data breach; you can use them to gain intelligence about any target online:
Have I been Pwned : This site lists half a billion real-world passwords previously exposed in data breaches. You can also download the Pwned Passwords list, which contains additional data about each breached account (such as the number of times that password had been seen in the source data breaches). This site can be searched using a target e-mail address or the password itself to see whether it appears in plain text on any public password dump list. This is a recommended site.
Breach Alarm : Enter your e-mail address to see whether your associated online account passwords have been exposed in a previous data breach. Results will get sent to the specified e-mail address.
Global Cyber Vandalism Statistics : This site holds information about the most active website hackers, most active hacker groups, recently hacked government and academic websites, recently reported hacked websites, and reported defacements on hold (not verified).
Hacked E-mails : Check anonymously whether your e-mail has been compromised in a previous data breach.