Dropbox breach seemingly caused by egregious authentication failure [U]
Multiple Dropbox users have been emailed by the cloud storage company to advise them that a security breach saw unauthorised access to their account. Update: the company has said that about 5,000 accounts were compromised, with files downloaded from around 1,500 of them. The root cause appears to be a lack of authentication by Dropbox when attackers created a single sign-on option through a…
![Dropbox breach seemingly caused by egregious authentication failure [U]](/img/5076083)
Multiple Dropbox users have been notified by the company that unauthorized access occurred to their accounts between August 4 and August 21, 2026. While no files were viewed or downloaded, Dropbox issued an email explaining the incident and providing guidance for affected users. The breach stemmed from a single sign-on (SSO) option facilitated through a third-party, Lenovo, that allowed attackers to register a Lenovo ID using a user's email address.
Despite Lenovo's email verification process failure, Dropbox failed to authenticate the linked ID prior to allowing access, which is considered a critical oversight. The company has since rectified this flaw and revoked all sessions previously authenticated via Lenovo ID.
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