Breach dump

A breach dump is a large file of data stolen from one or more organisations, shared or sold among criminals. Dumps often contain email addresses, usernames and passwords, and sometimes names, phone numbers, addresses or ID numbers. Criminals frequently merge many dumps into huge collections, sometimes called combolists, which can include billions of records gathered over many years. These collections are used to try leaked passwords on other websites, to write personalised scam messages, and to commit identity fraud. Because dumps are copied and reshared endlessly, data leaked long ago can still be in use today. This is why changing reused passwords and using a unique password for every site matters, even for breaches that happened years ago.