Intuitively, people tend to create passwords based on their personal information or a common combination of characters for easy memorization. Some common password combinations found in data breaches are "123456", "qwerty" and "password". Other common combinations include birth dates, own names, car brands and sports teams.
According to the Verizon Verizon Data Breach Investigations Report, compromised passwords are responsible for 81% of hacking-related breaches. In this case, ensuring users' password security should be an important part of overall information security.