An anonymous reader quotes a report from TechCrunch: The same hacker who leaked a trove of user data stolen from the genetic testing company 23andMe two weeks ago has now leaked millions of new user records. On Tuesday, a hacker who goes by Golem published a new dataset of 23andMe user information containing records of four million users on the known cybercrime forum BreachForums. TechCrunch has found that some of the newly leaked stolen data matches known and public 23andMe user and genetic information. Golem claimed the dataset contains information on people who come from Great Britain, including data from "the wealthiest people living in the U.S. and Western Europe on this list."

On October 6, 23andMe announced that hackers had obtained some user data, claiming that to amass the stolen data the hackers used credential stuffing -- a common technique where hackers try combinations of usernames or emails and corresponding passwords that are already public from other data breaches. In response to the incident, 23andMe prompted users to change their passwords and encouraged switching on multi-factor authentication. On its official page addressing the incident, 23andMe said it has launched an investigation with help from "third-party forensic experts." 23andMe blamed the incident on its customers for reusing passwords, and an opt-in feature called DNA Relatives, which allows users to see the data of other opted-in users whose genetic data matches theirs. If a user had this feature turned on, in theory it would allow hackers to scrape data on more than one user by breaking into a single user's account.