Security Incidents & Data Breaches

Across multiple years, attackers have built convincing fake Dropbox login pages — reached via PDF lures and redirect chains through trusted cloud storage — to harvest victims' real business email and Dropbox credentials.

A succession of episodes — the 2023 OpenAI default-on toggle, the 2024 Dropbox Sign breach and litigation, two rounds of mass layoffs, declining users, and serial product shutdowns — has coalesced into a durable narrative that Dropbox is a fading incumbent whose trust and relevance are eroding.

In January 2024 a 26-billion-record compilation dubbed the 'Mother of All Breaches' surfaced online — and the 68 million credentials stolen from Dropbox in 2012 were among the datasets bundled into it.

A tracked vulnerability in the Dropbox desktop application for Windows could strip the 'Mark of the Web' flag from synced files, weakening a key warning that protects users from running downloaded, untrusted content.

After Dropbox disclosed the April 2024 Dropbox Sign breach, affected users filed proposed class actions in federal court alleging Dropbox negligently failed to protect their data and did not give prompt, adequate notice; the claims are allegations and the consolidated litigation followed in the Northern District of California.

Beyond credential phishing, attackers have used Dropbox links to deliver malware — distributing remote-access trojans such as AsyncRAT through Dropbox-hosted archives and shortcut files that abuse the service's trusted reputation to get past defenses.

Within weeks of the Dropbox Sign breach disclosure, users filed a proposed class action in California federal court alleging Dropbox failed to protect their data and was slow to notify them.

Check Point recorded thousands of attacks in which criminals hosted credential-harvesting documents on Dropbox itself, so the phishing emails came genuinely from [email protected] and sailed past filters that trust the Dropbox domain.

An attacker compromised the production environment of Dropbox Sign (formerly HelloSign), exposing customer emails, usernames, phone numbers, hashed passwords, and authentication secrets including API keys, OAuth tokens, and MFA data.

Following the 2024 Dropbox Sign breach, affected users filed proposed class-action lawsuits accusing Dropbox of failing to secure their data and of notifying victims too slowly. Dropbox has contested the claims, arguing the exposed data poses no identity-theft risk.

State-aligned hacking groups, including North Korea's Kimsuky and ScarCruft, have repeatedly used the Dropbox API as a command-and-control and data-exfiltration channel, exploiting the fact that Dropbox traffic is trusted and rarely blocked.

Many third-party integrations request broad, full-Dropbox access rather than scoped, folder-limited permissions — so a single connected app, if compromised, can expose everything in an account.

A phishing campaign impersonating the CI provider CircleCI tricked Dropbox employees into handing over credentials and 2FA codes, letting attackers copy 130 of Dropbox's private source-code repositories.

ESET and Avast documented the Worok espionage group's 'DropBoxControl' backdoor, which abused the Dropbox API as its entire command-and-control channel — reading commands from, and uploading stolen data to, ordinary files in a Dropbox account.

The DropSmack proof-of-concept warned that synced Dropbox folders could be a covert C2 and exfiltration channel; multiple real malware families — including BoxCaon, Crutch and tooling used by Kimsuky — went on to abuse Dropbox folders and the Dropbox API exactly that way.

Dropbox's OAuth model historically let third-party apps request full account access, and tokens persist until revoked — so a single over-permissioned or compromised integration can read, write or delete a user's entire Dropbox without any further prompt.

Four years after the 2012 breach, the stolen credentials surfaced in the wild, forcing Dropbox to reset the passwords of all users who had not changed them since mid-2012.

Researchers revealed that Dropbox's Mac client used a user's admin password to directly edit macOS's protected TCC.db permissions database, inserting itself into the Accessibility list — a privacy/trust list that grants near-total control over the machine — without a clear, informed prompt.

When the full 2012 credential dump resurfaced in 2016, Dropbox forced a password reset on every user who had signed up before mid-2012 and never changed their password — a sweeping operational response that, for many, was the first sign anything was wrong.

At Black Hat USA 2015, Imperva researchers showed that stealing a single synchronization token let an attacker take over a Dropbox account and read its files indefinitely — and that, in Dropbox's case, changing the password did not revoke the stolen token.

Hackers claimed to have stolen nearly 7 million Dropbox logins, posted batches on Pastebin, and demanded Bitcoin — but the credentials came from other breached services, not Dropbox itself.

As thousands of intercepted Snapchat photos leaked in the so-called 'Snappening,' early reports tied Dropbox to the incident — but Dropbox flatly denied any involvement, and the actual leaks came from third-party apps and unrelated breaches, not Dropbox's systems.

Researchers found that Dropbox's shared links to supposedly private documents could leak to third parties — exposed through browser referer headers and, in some cases, surfacing in Google search results — revealing tax returns, bank records, and business plans.

On 10–11 January 2014 Dropbox went dark for roughly two hours after an internal maintenance error, while a group calling itself 1775 Sec falsely claimed to have breached it — a hoax that briefly stoked panic about user data.

At Black Hat Europe 2013, a researcher demonstrated 'DropSmack,' a technique that abused Dropbox sync to slip malware past corporate firewalls and quietly exfiltrate company files.

At USENIX WOOT 2013, Dhiru Kholia and Przemyslaw Wegrzyn unpacked and decompiled Dropbox's obfuscated-Python desktop client, demonstrated SSL interception via code injection, and described a way to hijack accounts and bypass two-factor authentication.

Q-CERT researchers found that because Dropbox did not verify email addresses at signup, an attacker who already had a victim's password could register a near-duplicate email, enable 2FA on it, and use the resulting emergency code to switch off the real account's two-step verification.

An attacker used a Dropbox employee's reused password to steal a file containing roughly 68 million users' email addresses and hashed passwords — a theft whose full scale only became public in 2016.

Researcher Derek Newton showed that Dropbox's desktop client stored an unencrypted authentication token (host_id) in a local config.db file — copy that one value to another machine and you owned the victim's account, with no password and no notification.

Security researcher Christopher Soghoian filed a complaint with the U.S. Federal Trade Commission alleging that Dropbox made deceptive claims about its encryption, because Dropbox employees could in fact access users' files.

For nearly four hours on 19 June 2011, a code update left Dropbox accounts accessible with any password at all — anyone could sign in to any account by typing anything.

Days after Dropbox disclosed the June 2011 bug that briefly let anyone sign into any account with any password, a plaintiff filed a class action alleging privacy and consumer-protection violations; the case was terminated within four months.