In what appears to be the largest data breach ever, attackers have leaked 3.2 billion passwords from multiple databases in a cyberattack dubbed RockYou2021. Users should immediately check to see if their passwords were affected by this leak, Tech Xplore says. Users can check for password compromise using the website Have I Been Pwned or the CyberNews personal data leak checker. Changing passwords might be an even better idea. Threat actors can take advantage of the RockYou2021 password collection by combining 8.4 billion unique password variations with existing breach compilations of email addresses and usernames. The hackers could then use these credentials for dictionary and password spraying attacks against an unknowable number of online accounts.