1. Adobe: October 2013

152 million Adobe user accounts were breached, leading to the details of 38 million users being compromised. Email addresses, passwords and usernames were made public after hackers raided a backup server. Adobe at the time was aware that its security system was inadequate but failed to take action before the breach happened.

2. Snapchat: January 2014

The so-called 'Snappening' led to 4.6 million Snapchat usernames and phone number being exposed. The details were posted on Redditwith hackers claiming they wanted to raise public awareness about Snapchat's poor cyber security. The hack was particularly controversial because of the private nature of many of the images sent via Snapchat.

3. eBay: February/March 2014

In February or March 2014 attackers stole details of 145 million eBay accounts, a breach eBay itself only became aware of in May 2014. Usernames, passwords, email addresses, phone numbers, physical addresses and dates of birth were all stolen in the attack using employee login credentials. eBay was criticised afterwards for failing to inform customers about the security breach in time.

4. Sony Pictures: November 2014

Sony Pictures had to shut down temporarily after hackers stole a large amount of documents. Soon to be released films and future production plans were posted online and emails calling Angelina Jolie a 'spoiled brat' were made public. The release of The Interview was cancelled after threats, leading to the suspicion North Korea was behind the attack. But to this day, it is still unclear who was really responsible.

5. Ashley Madison: July 2015

Adult dating website Ashley Madison was hacked then threatened that the stolen data would be released unless the website shut down. A month later 26 millions accounts were released with user's email addresses, GPS co-ordinates, credit card transaction details and sexual preferences revealed. It is possible to search the leaked data to find out who had an account on Ashley Madison and several prominent public figures have already been named.

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