Dropbox Sign customer data accessed in breach

Dropbox is reporting a recent “security incident” in which an attacker gained unauthorized access to the Dropbox Sign (formerly HelloSign) production environment. During this access, the attacker had access to Dropbox Sign customer information.

Dropbox Sign is a platform that allows customers to digitally sign, edit, and track documents. The accessed customer information includes email addresses, usernames, phone numbers, and hashed passwords, in addition to general account settings and certain authentication information such as API keys, OAuth tokens, and multi-factor authentication. The access is limited to Dropbox Sign customers and does not affect users of other Dropbox services because the environments are largely separate.

“We believe that this incident was isolated to Dropbox Sign infrastructure and did not impact any other Dropbox products.”

Even if you never created a Dropbox Sign account but received or signed a document through Dropbox Sign, your email addresses and names were exposed. In a government (K-8) filing about the incident, Dropbox says it found no evidence of unauthorized access to the contents of customers’ accounts (i.e. their documents or agreements), or their payment information. 

The attacker compromised a back-end service account that acted as an automated system configuration tool for the Dropbox Sign environment. The attacker used the privileges of the service account for the production environment to gain access to the customer database.

To limit the aftermath of the incident, Dropbox’s security team reset users’ passwords, logged users out of any devices they had connected to Dropbox Sign, and is coordinating the rotation of all API keys and OAuth tokens.

For customers with API access to Dropbox Sign, the company said new API keys will need to be generated and warned that certain functionality will be restricted while they deal with the breach.

Dropbox says it has reported this event to data protection regulators and law enforcement.


Dropbox expired affected passwords and logged users out of any devices they had connected to Dropbox Sign for further protection. The next time these users log in to their Sign account, they’ll be sent an email to reset the password. Dropbox recommends users do this as soon as possible.

If you’re an API customer, to ensure the security of your account, you’ll need to rotate your API key by generating a new one, configuring it with your application, and deleting your current one. Here is how you can easily create a new key.

API customers should be aware that names and email addresses for those who received or signed a document through Dropbox Sign, even if they never created an account, were exposed. So, this may impact their customers.

Customers who use an authenticator app for multi-factor authentication should reset it. Please delete your existing entry and then reset it. If you use SMS you do not need to take any action.

If you reused your Dropbox Sign password on any other services, we strongly recommend that you change your password on those accounts and use multi-factor authentication when available.

Protecting yourself from a data breach

There are some actions you can take if you are, or suspect you may have been, the victim of a data breach.

  • Check the vendor’s advice. Every breach is different, so check with the vendor to find out what’s happened and follow any specific advice they offer.
  • Change your password. You can make a stolen password useless to thieves by changing it. Choose a strong password that you don’t use for anything else. Better yet, let a password manager choose one for you.
  • Enable two-factor authentication (2FA). If you can, use a FIDO2-compliant hardware key, laptop, or phone as your second factor. Some forms of two-factor authentication (2FA) can be phished just as easily as a password. 2FA that relies on a FIDO2 device can’t be phished.
  • Watch out for fake vendors. The thieves may contact you posing as the vendor. Check the vendor website to see if they are contacting victims and verify any contacts using a different communication channel.
  • Take your time. Phishing attacks often impersonate people or brands you know, and use themes that require urgent attention, such as missed deliveries, account suspensions, and security alerts.
  • Set up identity monitoring. Identity monitoring alerts you if your personal information is found being traded illegally online, and helps you recover after.

Check your digital footprint

Malwarebytes has a new free tool for you to check how much of your personal data has been exposed online. Submit your email address (it’s best to give the one you most frequently use) to our free Digital Footprint scan and we’ll give you a report and recommendations.

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Cybersecurity risks should never spread beyond a headline. Protect your—and your family’s—personal information by using identity protection