Hundreds of Dropbox user login credentials were posted on Pastebin yesterday by a user who claimed to have 7 million more username-password combinations at the ready. The credential trader said they would release more logins if they received enough "support," in the form of Bitcoin donations.
Dropbox has confirmed that some of the stolen logins did indeed match those for Dropbox accounts, but also said that the company itself was not breached. In a statement to Reuters, a Dropbox representative said:
"These usernames and passwords were unfortunately stolen from other services and used in attempts to log in to Dropbox accounts. We'd previously detected these attacks and the vast majority of the passwords posted have been expired for some time now. All other remaining passwords have been expired as well."
Regardless of where the logins were lifted from and regardless of whether or not the logins will be bought and used by attackers, security experts say the real problem is single-factor authentication.
"Attacks like these demonstrate that, ultimately, the only way that we can stop or prevent password-based attacks is by the use of multi-factor authentication," says Jason Hart, vice president of cloud solutions at SafeNet. "Unless companies can categorically say they are doing this, then they will always be open to password-based attacks -- whether it actually happened or not."
Tod Beardsley, engineering manager at Rapid7, isn't sure that the attacker really has the 7 million Dropbox logins he claims to have.
"We saw this kind of claim after the news of the eBay breach – someone posted an ad saying they had the data from the eBay compromise and would sell it for Bitcoin," says Beardsley. "Analysis of the free 'sample' they offered revealed that the information was not from eBay at all. It is not necessarily the case that the same is true here – the data could be from Dropbox – but until Dropbox confirms a breach, or the data being offered is analyzed and verified as being from Dropbox, this is all just speculation."