Chegg

In April 2018 the online education platform Chegg suffered a massive data breach affecting approximately 40 million users. An unauthorized party gained access to a company database containing sensitive customer information. The compromised data included email addresses, usernames, and passwords stored as unsalted MD5 hashes which are considered cryptographically weak by modern standards. The incident was part of a broader trend of large scale credential thefts targeting academic services during that period.