MALL.cz data breach

Breach date: 2017-07-27. Added to this index: 2017-09-04. Accounts affected: about 735K. Domain: mall.cz.

What happened

In July 2017, the Czech Republic e-commerce site MALL.cz suffered a data breach after which 735k unique accounts including email addresses, names, phone numbers and passwords were later posted online. Whilst passwords were stored as hashes, a number of different algorithms of varying strength were used over time. All passwords included in the publicly distributed data were in plain text and were likely just those that had been successfully cracked (members with strong passwords don't appear to be included). According to MALL.cz, the breach only impacted accounts created before 2015.

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.
  • Names: Your first name, surname and sometimes middle name or initials, as you gave them when you signed up. It appears in almost every breach because nearly every account asks for it.
  • 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.
  • Phone numbers: Your mobile or landline number, collected at signup for contact, delivery updates, marketing and two-factor codes.

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 MALL.cz breach?

The MALL.cz breach exposed Email addresses, Names, Passwords, Phone numbers. About 735K accounts were affected.

Was I affected by the MALL.cz 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 MALL.cz 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