According to a collection of files obtained by Motherboard, containing the email addresses and hashed passwords of the affected user base, a total of 68,680,741 Dropbox accounts were successfully targeted during the 2012 hack. When Dropbox announced it was going through with the preventative password reset measure last week, the company didn't give any hint as to the extent of the users touched by the four-year-old hack.
The "incident," as Dropbox refers to it, was a data breach in the summer of 2012 where a few users began reporting spam sent to email addresses connected to a Dropbox account. Due to a password hack connected to other websites, hackers were able to sign in to "a small number" of Dropbox accounts, including an employee's who had access to a document listing an array of user email addresses.
Dropbox is confident its message to users last week has covered "all potentially impacted users," and the company is encouraging users to still reset passwords on other services that have the same login information, particularly passwords, previously used for Dropbox.
“We've confirmed that the proactive password reset we completed last week covered all potentially impacted users," said Patrick Heim, Head of Trust and Security for Dropbox. "We initiated this reset as a precautionary measure, so that the old passwords from prior to mid-2012 can’t be used to improperly access Dropbox accounts. We still encourage users to reset passwords on other services if they suspect they may have reused their Dropbox password.”As Motherboard discovered, nearly 32 million of the affected accounts were secured with the strong hashing function bcrypt, "meaning it is unlikely that hackers will be able to obtain many of the users' actual passwords." The other half of the passwords had a slightly less secure SHA-1 aging algorithm and were salted with a random string of characters to further strengthen them. Since 2012, Dropbox has changed up this password and account hashing process several times in attempt to make sure every user remains secure.
Motherboard confirmed that none of the four files, which total 5GB of collected user login data, appear to be anywhere on the dark web. Also, given Dropbox's aggressive measures taken in the past week, their value will continue to "diminish" over time.