What Is Credential Stuffing? How It Works and How to Prevent It
Credential stuffing is one of the most common and dangerous forms of cyberattacks today. If you’ve ever reused a password across multiple accounts, you could be at risk. In this post, we’ll break down what credential stuffing is, how it works, how it’s different from brute-force attacks, and most importantly — how to protect your business and users from credential stuffing attacks.
What Is Credential Stuffing?
Credential stuffing is a type of cyberattack where hackers use stolen usernames and passwords — often obtained from data breaches — to gain unauthorized access to user accounts across multiple websites or applications.
The attack relies on the fact that many people reuse the same credentials across multiple online services. If a user’s login credentials are exposed in one breach, attackers will try using them on other websites — a method called “stuffing” the credentials into login pages using automated bots.
How Does Credential Stuffing Work?
Here’s a typical credential stuffing attack flow:
- Data Breach: Login credentials (emails/usernames and passwords) are leaked or sold on the dark web after a data breach.
- Credential List Creation: Attackers compile large lists of stolen credentials — sometimes millions at a time.
- Bot Automation: Using bots, attackers test these credentials across various websites, especially those with login portals (banking, eCommerce, email services, SaaS tools, etc.).
- Account Takeover: When a match is found, the attacker gains access to the account and may steal data, make purchases, or resell the account.
Credential Stuffing vs Brute Force Attacks
Many people confuse credential stuffing with brute-force attacks, but there are key differences:
- Credential Stuffing: Uses real username-password pairs stolen from breaches.
- Brute Force Attacks: Involve guessing passwords by trying many combinations (e.g., dictionary attacks).
Credential stuffing is faster and more successful, especially when users reuse passwords across multiple services.
Real-World Credential Stuffing Examples
Credential stuffing has affected some of the world’s biggest brands. A few notable cases include:
- Spotify (2020): Hackers used credential stuffing to access user accounts and change account settings.
- Zoom (2020): Over 500,000 Zoom credentials were found on hacker forums, many of which were harvested using credential stuffing.
- Nintendo (2020): Hackers used this method to access over 160,000 user accounts and make unauthorized purchases.
These examples show how widespread and damaging credential stuffing attacks can be.
Why Credential Stuffing Is Dangerous
Credential stuffing attacks can lead to:
- Account Takeover (ATO)
- Financial Fraud
- Identity Theft
- Reputation Damage
- Loss of Customer Trust
Even if your platform hasn’t experienced a breach, your users might have reused their passwords from another compromised site.
How to Prevent Credential Stuffing Attacks
1. Implement Multi-Factor Authentication (MFA)
MFA adds an extra layer of security. Even if credentials are correct, the attacker can’t log in without the second factor.
2. Detect and Block Bots
Use bot detection tools and rate-limiting to identify unusual login activity. Web Application Firewalls (WAFs) with bot mitigation capabilities are particularly effective.
3. Monitor Login Patterns
Keep an eye on IP addresses, geolocation, and abnormal login times. Anomalies can signal a credential stuffing attempt.
4. Use Credential Stuffing Protection Tools
Services like CyberVolt’s Credential Defense Suite offer real-time monitoring, bot protection, and automatic blocking of known malicious login patterns.
5. Educate Users
Encourage users to use strong, unique passwords and avoid reusing passwords across platforms. Promote password managers to help manage multiple secure passwords.
6. Dark Web Monitoring
Use threat intelligence tools to monitor for your users’ credentials on dark web forums. If found, proactively alert affected users to reset passwords.
7. Apply Login Rate Limits
Rate-limiting login attempts per user/IP address helps slow down or block automated credential stuffing attacks.
Final Thoughts
Credential stuffing is a fast-growing threat in today’s digital world — especially for businesses that rely on login-based platforms. Understanding the risk of credential reuse, and implementing strong defenses like multi-factor authentication, bot protection, and user education, can significantly reduce your risk.
Protect Your Business from Credential Stuffing Attacks
CyberVolt provides enterprise-grade solutions to detect, block, and mitigate credential stuffing attacks. From advanced bot detection to login behavior analytics, we help businesses secure their digital environments.
🔐 Secure your applications today — contact CyberVolt for a free security consultation.
