You’ve come up with a strong password. It ticks every recommended password security box: numbers, uppercase letters scattered around, a couple of well-placed “^” and “$” symbols, and it ends with an upside-down question mark. It’s perfectly designed to be the single safest password for every account you own. Unfortunately, reusing the same password — regardless of how complex it is — runs the risk of compromising your entire online presence if it gets breached. Let’s talk about credential stuffing attacks, how they impact accounts with reused passwords, and what you can do to stay safe.
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What is credential stuffing, and how does it work?
Credential stuffing is a type of cyberattack in which criminals use stolen credentials to gain unauthorized access to user accounts or organizational systems. They usually get usernames and passwords for these scams from leaked databases on the dark web.
As the name suggests, credential stuffing attacks are designed to “stuff” as many stolen login combinations as possible into multiple websites or company systems in hopes of gaining access to them. Credential stuffing relies on automation and the assumption that many people reuse login details across multiple online services and platforms.
Why is credential stuffing on the rise?
According to supplementary research for Verizon’s 2025 Data Breach Investigations Report (DBIR), compromised credentials were the primary method of access in nearly a quarter of all breaches reviewed. Many of those credentials were compromised during a credential stuffing attack. In fact, the report states that 19% of daily authentication attempts were made via credential stuffing. The highest percentage of credential stuffing attempts recorded in a single day was 44%.
Credential stuffing attacks are common thanks to their effectiveness. Cybercriminals have the precise login details to test, and although they can’t confirm this data is still in use, they figure it out relatively quickly. They use bots and automated systems to rapidly test many login combinations from the breached databases and see which accounts they can access. If users don’t have multi-factor authentication (MFA) set up, those accounts are as good as stolen.
The data cybercriminals use is easy to obtain — stolen credentials can cost as little as a dollar, so even if some logins don’t work, it’s not a big financial loss for the hackers. Credentials also often come in data sets containing thousands or even millions of individual records, which give criminals ample testing material.
Once the data pool has been gathered, hackers start sending out hundreds of automated login requests across multiple services to check which ones work. If a set of login credentials works on a major platform, hackers will likely test it again on other websites or apps. Considering that an average person has around 168 accounts, the chances of a password being reused are pretty high.
Credential stuffing vs. brute-force attacks
On the surface, credential stuffing and brute-force attacks work similarly. Bad actors attempt to gain access to online accounts or corporate systems to overtake them, steal sensitive information, or otherwise compromise them.
However, the two attacks differ in their approach. During brute-force attacks, criminals use automated processes to guess as many potential matches of the targets’ login credentials as possible. According to Adrianus Warmenhoven, attackers use AI-assisted tools to predict login credential patterns and maximize the volume of compromised data, which leads to more effective attacks.
For credential stuffing attacks, criminals use data they’ve gathered from breach databases, meaning they know the combinations have already worked somewhere, although they might not know the precise website or system. This makes credential stuffing more successful than brute-force attacks.
How to prevent credential stuffing attacks
Preventing credential stuffing comes down to the fundamental issue behind many other cyberattacks — keeping credentials safe. Unfortunately, criminals often target service providers directly. If the providers don’t offer sufficient protection from breaches, you can’t do much to keep your data secure. However, you can employ basic security practices to reduce the chances of being a victim of a credential stuffing attack.
Do not reuse passwords
We’ve already hinted at it — reusing a single password for every single account, no matter how strong you believe it is, is a recipe for disaster. Even using it for two accounts automatically increases the risk of it being compromised. If the platform gets hacked and the password lands in a data bundle somewhere on the dark web, nothing can stop cybercriminals from acquiring it and testing it out in a credential stuffing attack.
To keep your personal data secure, never reuse the same password. Instead, you can use a password generator to create a unique and complex password for each account you use. You can adjust the password length, complexity, and decide which symbols you want to include or exclude. We recommend generating a password that’s at least 15 characters long and uses a random combination of uppercase and lowercase letters, numbers, and special symbols.
Set up multi-factor authentication
Multi-factor authentication is an additional step of identity verification that activates when you try to log in to any of your online accounts. One of the most common MFA types is a multi-digit code you need to enter after using your login credentials. Usually, the code is sent to you via email or generated by an authenticator. Using multi-factor authentication means that even if cybercriminals try to use your stolen login details for credential stuffing, they can’t succeed without access to the MFA code on your device.
Get a password manager
Recommendations to keep unique passwords for each account can be overwhelming, especially if you have to juggle personal and work-related credentials. However, a password manager easily solves this problem. This tool helps you to securely store and access your passwords, credit cards, and other personal information whenever you need it.
With a password manager like NordPass, you can create, store, and manage your login credentials with ease. It eliminates the need to manually type passwords and usernames by autofilling matching credentials from the vault to the website or app. NordPass automatically detects new login details and lets you save them with a single click, which helps you save time and avoid the frustration of accidental mistypes and forgotten passwords.
Regularly check if your credentials have been leaked
Knowing if your username or password has been compromised is critical in preventing a credential stuffing attack and maintaining account security. Some websites let you view user activity and display data like failed login attempts, including when and where they occurred, which helps you determine when your password might have become available to cybercriminals.
However, you can’t manually track the login activity of every single website you’re using for data breaches. Although you should get alerted when a platform experiences a breach that impacts your personal data, by the time this official communication arrives, it may be too late. Instead, you can set up a dark web monitoring tool like NordPass’ Data Breach Scanner. It automatically tracks the dark web for your personal data, like your passwords, email addresses, and credit card details, and sends you a notification as soon as it finds a match.
Trust fingerprinting and behavioral analysis to prove your identity
Credential stuffing relies heavily on bots to automate and rapidly attempt to gain unauthorized access. These bots have their own unique digital fingerprint that helps identify them and set them apart from real, human users. Whenever you log in to a website yourself, you create a fingerprint that the service provider can use to identify you. If a bot is used to input login credentials without your knowledge, the website would recognize the mismatching fingerprint and trigger a security response, like a CAPTCHA request, or block access altogether.
Behavioral analysis is a more technical approach to credential stuffing prevention. It allows platforms to tell human users apart from bots through behavioral biometrics, like mouse movements, typing pace, and time spent on the page. If the website detects little to no cursor movement, an unusually fast click-through rate and typing pace, or unnatural credential input through automated copying and pasting, it can flag this behavior as botlike and prevent the login attempt from succeeding.
Bottom line
Credential stuffing attacks have a high success rate, but they’re easily avoidable if you follow secure credential management practices. Changing a single password from your usual to a unique one makes at least one account safer from cybercriminals. With NordPass Premium, you can easily update all your login details, set up multi-factor authentication directly in your vault, and keep a constant eye on vulnerable and compromised credentials with features like Password Health. Stay vigilant and don’t let criminals compromise your account safety.