Collection #1 data breach

Breach date: 2019-01-07. Added to this index: 2019-01-16. Accounts affected: about 773M. Domain: not listed.

What happened

In January 2019, a large collection of credential stuffing lists (combinations of email addresses and passwords used to hijack accounts on other services) was discovered being distributed on a popular hacking forum. The data contained almost 2.7 billion records including 773 million unique email addresses alongside passwords those addresses had used on other breached services. Full details on the incident and how to search the breached passwords are provided in the blog post The 773 Million Record "Collection #1" Data Breach.

Breach data sourced from Have I Been Pwned, used under CC BY 4.0. Additional breach metadata provided by XposedOrNot. DataExposed is an independent service and is not affiliated with or endorsed by either.

What was exposed

  • Email addresses: The email address you used to register or log in. It is the most common field in breaches because it doubles as your username on most sites.
  • Passwords: The secret you use to sign in, stored by the breached service either in plain text, in a scrambled form called a hash, or encrypted. How it was stored decides how quickly it can be recovered.

What to do now

  1. Check whether your own address is in this dataset with the free email breach check.
  2. Change the password on this service and every other site where you used the same password.
  3. Turn on two-factor authentication on your email account first, because it is the reset path for everything else.
  4. Treat calls and messages that quote real details about you as hostile until you verify them another way.

Frequently asked questions

What data was leaked in the Collection #1 breach?

The Collection #1 breach exposed Email addresses, Passwords. About 773M accounts were affected.

Was I affected by the Collection #1 breach?

Run the free email breach check with the address you used on that service. It will tell you whether your address appears in this dataset.

What should I do about the Collection #1 breach?

Change the password on that account and everywhere you reused it, then turn on two-factor authentication. Passwords from this breach are traded and tried automatically against other sites.

Next steps