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The most dangerous data breaches in history were caused by hackers and human error.
This fact was showcased on Monday when news broke affair site Ashley Madison had fallen victim to hackers and had an undisclosed number of its customers' personal details leaked online.
So we have collected information from the Open Security Foundation (OSF), DataLossDB initiative to rank and detail the 19 worst hacks in history.
The ranking is based on the number of customer records compromised during the incident. If the number of compromised records during a data breach were identical we ranked them by date, putting the oldest first.
We didn't include data breaches where, for legal reasons, the company involved cannot be named.