6 most effective techniques to prevent credential stuffing

Credential stuffing is an automated cyberattack where hackers use stolen username-password pairs to gain unauthorized access to user accounts across multiple websites. Credential stuffing prevention is one of the most effective cybersecurity defenses a website or organization can implement today. Securing and protecting your users' data with account takeover prevention methods can go a long way toward stopping costly and damaging breaches.

Credential stuffing attacks are among the most common causes of data breaches. This technique is made possible because around 94% of people reuse passwords on multiple accounts rather than using a password manager to generate unique passwords, meaning that once attackers have that information, reusing it across other sites is trivial. Data breaches, many of which originate from credential stuffing, cost U.S. organizations an average of $9.48M according to IBM's 2024 Cost of a Data Breach Report.

The scale of credential stuffing attacks is only increasing globally. Billions of credentials are exposed in data breaches each year, with attackers using automated tools to test these stolen credentials across thousands of websites simultaneously. The success rate may be low (around 0.1-0.2%), but the sheer volume of attempts makes credential stuffing highly profitable for attackers.

What is credential stuffing?

Credential stuffing is the automated use of usernames and passwords obtained through data breaches, phishing campaigns, or purchases on dark web marketplaces. These hacks can be coordinated by the party carrying out the credential stuffing attack, or cybercriminals can purchase pre-obtained logins from the dark web.

Automation bots rapidly enter stolen login details across many websites simultaneously. While they're rare, a successful login can expose personal information, saved payment methods, or other sensitive account data.

Credential stuffing attacks are popular because they can sweep a wide range of sites much faster than entering the information manually. Not only that, but bots can distribute their requests from different IP addresses, making simple IP-based blocking ineffective.

What is the difference between credential stuffing and brute force attacks?

Credential stuffing, password spraying, and brute force attacks are all automated login attacks used to gain access, but they work differently. Credential stuffing uses known username-password pairs stolen from previous data breaches, while brute force attacks systematically guess passwords using random combinations or dictionary words. Password spraying takes the opposite approach, trying a small number of commonly used passwords against many different accounts to avoid lockout thresholds. Credential stuffing is typically more effective because it exploits password reuse across multiple sites.

Famous credential stuffing attacks

Even if you haven't heard the term credential stuffing attack before, there's a good chance you may have heard of one being carried out:

• In 2020, around 500,000 usernames and passwords were stolen from Zoom, published on the dark web, and made available for purchase.
• The North Face has fallen victim to  credential stuffing attacks four times in the past few years including an information leak of nearly 200,000 users in 2022 and another recent incident in 2025. 
• In 2025, DraftKings warned users of an attack after hackers accessed user accounts and compromised names, addresses, phone numbers, email addresses, and other information.

The list goes on. While the information in a single North Face account may seem insignificant, when the same password is used for an online bank account, it can become a much larger (and more expensive) problem.

Checklist for credential stuffing prevention

So what can you do to protect your users’ accounts against credential stuffing, beyond simply requiring strong passwords? It may require extra effort, but the payoff can be protecting your users’ personal data, personal information, and widespread access to other accounts.

Here are the most effective techniques to protect yourself from credential stuffing attacks:

1. Multi-factor authentication (MFA): A security method requiring users to verify their identity through a secondary device, biometric scan, or authenticator app before accessing their account. MFA can be integrated via a separate app such as Duo or JumpCloud. When a user logs in, the MFA provider pushes a notification to their registered device to confirm the attempt. MFA is easy to set up, and many platforms are now incorporating it as a standard part of the login process.
2. IP blocking: A security measure that denies connections from specific IP addresses or regions identified as suspicious. You can block access at the server or WAF level based on region or flagged IP ranges. Blocking IP addresses is particularly effective when you can identify suspect IP addresses repeatedly attempting login attempts against your system. However, it loses effectiveness when those IP addresses are randomized or rotated, which is common in credential stuffing operations.
3. Device fingerprinting: A technique that uses browser and device attributes to create a stable and unique identifier for each visitor. Also known as browser fingerprinting, it's based on your browser and device settings, such as screen resolution, GPU capabilities, language, and operating system. Fingerprint's device identification generates a persistent visitor ID that can detect when the same device attempts logins across multiple accounts or when a known bad actor returns — even after clearing cookies or changing IPs. This allows you to recognize and block repeat attackers regardless of the account they target.
4. Bot detection: Technology that identifies and blocks automated scripts, headless browsers, and other automation tools attempting login abuse. Fingerprint's Bot Detection Smart Signal can block credential stuffing bots by analyzing visitors and returning notDetected when no bot activity is found, good for known legitimate bots like search engines or verified AI agents, and bad for automation tools and headless browsers. 
5. Rate limiting: A defense mechanism that restricts the number of login attempts allowed from a given user, device, or IP address within a defined time window. When a threshold is exceeded, subsequent attempts can be blocked, delayed, or challenged with step-up authentication. Rate limiting is one of the most straightforward controls to implement and is effective against low-sophistication attacks. It becomes less effective against distributed credential stuffing operations where requests are spread across many IP addresses and timed to stay under detection thresholds, making it most effective when combined with device fingerprinting or bot detection.
6. Breach credential checking: At login or account creation, you can check submitted passwords against known breach datasets using a service like the Have I Been Pwned API. If a credential pair appears in a known breach, you can prompt the user to reset their password before granting access. Not essential, but a low-effort integration that adds a meaningful layer of protection for users who reuse passwords across sites.

Protect your users from credential stuffing before attackers find the gaps

Credential stuffing attacks are increasing in scale and sophistication, and the cost of a breach, financial, legal, and reputational, can be significant and long-lasting. A proactive approach to credential stuffing prevention means building the right controls into your authentication layer before attackers find the gaps: rate limiting to slow automated attempts, bot detection and device fingerprinting to catch distributed attacks that evade IP-based defenses, and MFA to ensure compromised credentials alone aren't enough to gain access.

Fingerprint gives you the device intelligence to make smarter authentication decisions at every login. Talk to our team to see how it fits into your stack, or create a free account and get started.