Hackers have leaked hundreds of emails and passwords online after claiming to have stolen 7 million individual login credentials from popular cloud storage service Dropbox.
In a series of posts to the website Pastebin, an anonymous "guest" dropped three "teasers" each containing hundreds of emails and passwords from "Hacked Dropbox accounts".
Links to the Pastebin posts were also published on Reddit.
The user promised to release more details the more money people donated, using the cryptocurrency Bitcoin.
"Get at them while they are hot," the user posted.
Dropbox released a statement to media outlets denying its systems had been hacked. It also said most of the login details were old.
"These usernames and passwords were unfortunately stolen from other services and used in attempts to log in to Dropbox accounts," the company told The Next Web.
"We'd previously detected these attacks and the vast majority of the passwords have been expired for some time now."
Dropbox has disabled the leaked passwords and has forced affected users to create new ones, according to the website.
All Dropbox customers are advised to change their passwords and switch on two-factor authentication, which requires logging in with a security code sent to your phone when accessing your account from a new device.
News of the breach comes as Dropbox staff were accused of booting local teenagers out of a public soccer field in San Francisco's trendy Mission District because they didn't have a permit to play. Video of the heated exchange went viral, gathering nearly 300,000 views at the time of writing. Dropbox has since apologised.