Credential Stuffing vs Password Spraying

Credential Stuffing vs Password Spraying

This ethical hacking guide explores the differences between credential stuffing and password spraying attacks along with their prevention in cyber security.

What is Credential Stuffing?

Credential stuffing is a type of cyber attack where attackers use lists of compromised usernames and passwords from previous data breaches to gain unauthorized access to user accounts on different websites and services. The attack relies on the common practice of users reusing the same password across multiple accounts.

How Credential Stuffing Works:

  1. Data Breach: Usernames and passwords are stolen from a compromised website or service.
  2. Credential Lists: These stolen credentials are compiled into lists and often sold or shared on the dark web.
  3. Automated Login Attempts: Attackers use automated tools to try the stolen credentials on various websites, hoping that users have reused the same username and password combination.
  4. Account Takeover: If the credentials are valid on another site, the attacker gains access to the user’s account.

What is Password Spraying?

Password spraying is a type of cyber attack in which an attacker attempts to gain unauthorized access to a large number of user accounts by systematically trying a few commonly used passwords against many different usernames. Unlike brute force attacks, which try many passwords on a single account, password spraying spreads the attempts across many accounts, thus avoiding account lockouts due to failed login attempts.

How Password Spraying Works:

  1. Collecting Usernames: The attacker gathers a list of valid usernames for the target system. This can be done through various means such as phishing, social engineering, or exploiting information leaks.
  2. Common Passwords: The attacker compiles a list of common or default passwords. These might include simple, commonly used passwords like “password123”, “123456”, or “welcome”.
  3. Systematic Attempts: The attacker tries each common password against all usernames in their list. For example, they might try “password123” against all accounts before moving on to “123456”.
  4. Avoiding Detection: Because they are only trying a few passwords per account, attackers can often evade detection mechanisms that lock accounts after multiple failed login attempts.
  5. Gaining Access: If successful, the attacker gains access to accounts where the common password was a match, potentially leading to further exploitation or data breaches.

Credential Stuffing vs Password Spraying

Here’s a comparative table outlining the main differences between credential stuffing and password spraying attacks:

AspectCredential StuffingPassword Spraying
Source of PasswordsUses previously breached or leaked credentials.Uses commonly used passwords likely to be chosen by some users.
Attack FocusAttempts on multiple sites with known credentials.Attempts on many accounts with a few passwords.
MethodologyAutomated login attempts using known username-password pairs.Automated login attempts using common passwords across users.
Prevention ComplexityRequires advanced security measures like MFA, CAPTCHA, etc.Can be mitigated by enforcing account lockout policies and strong password guidelines.
User ImpactAffects users who reuse passwords across different services.Targets a wide array of users, regardless of password reuse.
Detection DifficultyHarder to detect due to valid credential usage.Easier to detect due to the use of common passwords.
Credential Stuffing vs Password Spraying

Prevention and Mitigation

Credential Stuffing:

  • Implement multi-factor authentication (MFA) wherever possible.
  • Employ advanced security solutions like CAPTCHA and device fingerprinting.
  • Encourage or enforce unique passwords for different sites.

Password Spraying:

  • Enforce strong password policies that prohibit common passwords.
  • Enforce account lockout policies after a certain number of failed login attempts.
  • Enable 2FA to add an extra layer of security.


Understanding the differences between Credential Stuffing and Password Spraying is essential for implementing effective cybersecurity measures. By recognizing the characteristics and attack methods of each, organizations can better protect their systems and user accounts from these types of attacks.

Implementing a combination of strong password policies, multi-factor authentication, and monitoring systems can significantly reduce the risk posed by these threats.

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