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Threats · Beginner · 3 min

Data breaches

Your data is probably already out there. Here's what that means.

What it is

A data breach is when information is accessed or taken by someone who shouldn't have it. It can be a hack, a misconfigured database left open to the internet, or an insider. Stolen data is sold, leaked or used for further attacks. Reused passwords from one breach get tried on other sites, which is called credential stuffing.

Real case · 2023

MOVEit

The Cl0p gang used a SQL injection zero-day in MOVEit Transfer, a file-sharing product, to steal data from over 2,700 organisations in one campaign, exposing personal data on roughly 93 million people.

Source: Wikipedia: 2023 MOVEit data breach

How defenders stop it

  • Collect and keep less data
  • Encrypt sensitive data and lock down database exposure
  • Unique passwords and a password manager for everyone
  • Monitor for leaked company credentials

Try it yourself

Check your email on Have I Been Pwned

Check yourself

1. What is credential stuffing?

  1. Guessing passwords one letter at a time
  2. Trying leaked username/password pairs on other sites
  3. Putting too many passwords in a manager
  4. Encrypting stolen passwords
Show answer

Trying leaked username/password pairs on other sites. It works because people reuse passwords. Unique passwords stop it.

2. Which of these is a data breach?

  1. A software update is installed
  2. The office network is slow
  3. A stranger downloads a customer database that was left open to the internet
  4. A website goes offline for an hour
Show answer

A stranger downloads a customer database that was left open to the internet. A breach is any access to data by someone who shouldn't have it. Misconfigured, exposed databases count, not only hacks.

3. What stops credential stuffing from working on your accounts?

  1. The same strong password everywhere
  2. Clearing your cookies
  3. A different password for every site, kept in a password manager
  4. Changing your username
Show answer

A different password for every site, kept in a password manager. Credential stuffing replays passwords leaked from one site on others, so it only works when a password is reused.

Answer them in the app to earn XP.

Next: Nation-state hackers (APTs) →