2. LinkedIn Password Breach
An attacker made off with nearly 6.5 million LinkedIn passwords in a breach that was announced last year. The stolen passwords, which were hashed, were posted to a Russian hacking forum where the attackers sought help in cracking them. Within days, more than half of the passwords were cracked. Because victims often use the same passwords for other accounts, the breach impacted other online services including Facebook, eHarmony and radio streaming site Lastfm. The breach forced some of the other online services to reset the victim's accounts. The cybercriminals apparently used a SQL injection attack to gain access to the LinkedIn back-end servers containing the password data.