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What is Credential Stuffing and How to Protect Yourself

What is Credential Stuffing and How to Protect Yourself
Photo by Elisa Ventur / Unsplash

Credential stuffing is a type of cyberattack that exploits the reuse of usernames and passwords across different websites and applications. It uses automated tools to test stolen credentials against various online services, hoping to find a match and gain unauthorised access. Credential stuffing is one of the most common and effective ways of hacking into accounts, as it can bypass many security measures such as passwords, captchas, and two-factor authentication.

How Does Credential Stuffing Work?

Credential stuffing involves three steps:

  1. A hacker obtains a list of usernames and passwords from a data breach, a phishing attack, or a dark web marketplace. These lists may contain millions or billions of login pairs exposed by previous breaches or leaks.
  2. The hacker uses an automated bot program to try each username and password combination against multiple websites, using different IP addresses, browsers, and devices to avoid detection.
  3. If the hacker finds a successful login on one website, they can use the same credentials to access other websites with the same username or email address.

Credential stuffing is challenging to detect because it mimics normal login traffic and does not leave any obvious signs of malicious activity. However, some websites may have security features that can help identify credential stuffing attacks, such as:

  • Captchas: These are puzzles or challenges that require human intelligence to solve before allowing access. They can verify that the user is not a bot or an automated program.
  • Rate-limiting: This technique limits the number of login attempts per user or IP address within a specific time period. It can be used to prevent bots from overwhelming the server with requests.
  • Device fingerprinting: This technique analyses the characteristics of the device used by the user, such as screen resolution, browser type, operating system version, etc. It can distinguish between human and bot users based on their device behaviour.

How Can You Prevent Credential Stuffing Attacks?

The best way to protect yourself from credential stuffing attacks is to use strong and unique passwords for each website you use. A strong password should be at least 12 characters long, include uppercase and lowercase letters, numbers, and symbols, and avoid common words or phrases. A unique password means that you do not use the same password for more than one account.

To create and manage your passwords securely, you can use a password manager tool that offers features such as:

  • Password generator: This tool can create random and complex passwords based on your preferences.
  • Password storage: This tool can store your passwords in an encrypted digital vault that only you can access with your master password.
  • Password synchronisation: This tool can sync your passwords across all your devices so that you do not have to remember them manually.

I recommend Dashlane.

Another way to prevent credential stuffing attacks is to enable multi-factor authentication (MFA) whenever possible. MFA adds an extra layer of security by requiring something you know (such as your password), something you have (such as your phone), or something you are (such as your fingerprint) in addition to something you know.

MFA can make it harder for hackers to access your accounts even if they have your username and password. However, MFA may not be available or feasible for all applications due to technical limitations or user preferences.


Credential stuffing is a serious threat that can compromise your online accounts and personal information. To protect yourself from this attack, you should follow these best practices:

  • Use strong and unique passwords for each website and application
  • Use a password manager tool
  • Enable multi-factor authentication whenever possible
  • Monitor your account activity regularly
  • Educate yourself about security tips

By following these steps, you can reduce the risk of becoming a victim of credential stuffing attacks and enjoy a safer online experience.

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