An anonymous reader writes Back in August, groups of Russian hackers assembled the biggest list of compromised login credentials ever seen: 1.2 billion accounts. Now, domain registrar Namecheap reports the hackers have begun using the list to try and access accounts. "Overnight, our intrusion detection systems alerted us to a much higher than normal load against our login systems. ... The group behind this is using the stored usernames and passwords to simulate a web browser login through fake browser software. This software simulates the actual login process a user would use if they are using Firefox/Safari/Chrome to access their Namecheap account. The hackers are going through their username/password list and trying each and every one to try and get into Namecheap user accounts." They report that most login attempts are failing, but some are succeeding. Now is a good time to check that none of your important accounts share passwords.