Credential stuffing and brute force attacks are two of the most common ways cybercriminals hack into password-protected systems. These account takeovers can allow unauthorized access to all kinds of sensitive data, from bank accounts to customer emails.
If you fail to follow certain best practices, such as eliminating passwords and limiting login attempts, these threats can quickly penetrate and spread across your organization. You’ll need security solutions that take common attacks into account and protect your network from multiple angles.
So in this guide, we’ll explain the fundamentals behind credential stuffing versus brute force attacks. Then we’ll build on that understanding to explore security best practices that can prevent both types of hacking.
What Is Credential Stuffing?
The term “credential stuffing” means an automated attack strategy where hackers harvest stolen login credentials from a data breach to access other services or websites. Instead of trying to guess passwords, they bet on the knowledge that many people reuse credentials across multiple platforms.
One 2025 World Password Day study found that password reuse is dangerously common, especially among younger generations. While 72% of Gen Z reused passwords, only 42% of Boomers did. Younger people were also more likely to reuse existing credentials when prompted to change their passwords.
This is a problem because once hackers obtain usernames and passwords from one breach, they can run that data across many other endpoints. Thanks to artificial intelligence, they no longer need to do this manually and can instead use bots and proxy networks. Hackers also avoid detection by using headless browsers and rotating IP addresses.
What Is a Brute Force Attack?
Brute force hacks rely on automated password guessing. Malicious actors use AI tools to systematically test combinations of passwords and usernames until they find a correct pair. Hackers can significantly improve their computation times by trying common passwords, along with slight modifications on credentials obtained from previous data breaches.
The same 2025 World Password Day study we looked at earlier shows that these techniques can be very effective. People often only make small changes to their passwords when prompted to create new ones. On average, the study found that 17–18% of people across all generations changed just one character from an old password, while 28–34% changed only a few characters.
These user behaviors make it easier for cybercriminals to write effective scripts that iterate quickly through password dictionaries and character combinations. This problem compounds when hackers combine brute force account takeovers with password spraying, where they try password combinations using multiple accounts to prevent lockouts.
Key Differences Between Credential Stuffing and Brute Force Attacks
Brute force and credential stuffing attacks share an end goal: accessing user accounts to gain sensitive data. There are other similarities between these identity-based attacks—for example, both methods generally use automated tools and previously known passwords.
However, there are some important differences that security teams must consider to find effective solutions:
- Source of credentials: A credential stuffing attack uses known credentials from a past data breach, while brute force hacks generate guesses through automation. Cybercriminals can combine both for maximum effect.
- Attack mechanics: Credential stuffing exploits the reuse of stolen usernames and passwords, which are often sold on the dark web. Meanwhile, brute force usually exploits weak or predictable passwords by systematically testing possibilities.
- Attack signature: Credential stuffing often appears as successful logins with valid credentials, sometimes spread across multiple IPs. However, brute force tends to generate repeated failed login attempts for the same account.
- Required resources: Credential stuffing is cheap and efficient when attackers have breach data to work with. Brute force can be computationally expensive and time-intensive, unless combined with other methods like password spraying.
6 Ways to Prevent Credential Stuffing and Brute Force Attacks
Cybercriminals rely on poor password hygiene to successfully hack systems. This means the best interventions begin at the user level. But you can’t stop there—strong security posture requires a comprehensive, multi-layered solution that incorporates technical and administrative policies.
1. Set Strong Password Requirements
Whether or not you reuse passwords, you can make them harder to crack in the first place. As a part of their credential management policies, companies should set and enforce password rules that make strong, unique passwords mandatory.
A “strong” password often includes:
- At least 12 characters, often more
- Lower and uppercase letters
- Numbers
- Special characters
- Randomized elements (no name, dates, or other identifiers)
2. Use Authorized Password Vaults
Unfortunately, strict password requirements and frequent change requests can backfire. When people have to change their passwords every month or quarter, it becomes difficult to keep up, especially if passwords expire at different times. They may give up on good password hygiene entirely, and it’s hard to enforce best practices consistently across an entire organization.
So instead of requiring frequent changes, it can be best to have users set very strong and unique passwords, then use a vault like LastPass or 1Password to secure and track them.
3. Limit Login Attempts
How many times should a user be allowed to log in before you lock their account? Unlimited attempts make it much easier for hackers to gain access, but locking genuine users out immediately can frustrate them.
Instead, you can allow for a set number of tries within a certain period. For example, you might let a user try to log in three times, then lock up their account for one hour. Real users get a few attempts, while bad actors are quickly driven away.
4. Enable Multi-Factor Authentication
Multi-factor authentication (MFA) can prevent or slow down all kinds of cyberattacks. MFA typically requires a user to sign in with a password and then go through a secondary authentication process, such as entering a code sent to their email address or mobile phone.
This makes it difficult for hackers to access systems even if they have the right credentials. They would also need access to the user’s personal device or email account. And because successful logins prompt another request, often via email or text, the real user is made aware of the attempt.
5. Eliminate Passwords
Some companies are going a step further by getting rid of passwords altogether or limiting their use whenever possible. Instead, they require alternate sign-in methods that are harder to duplicate, such as:
- Physical passkeys
- Biometric data (e.g., fingerprints)
- Single sign-on (SSO)
- Pins and patterns
6. Conduct Regular Monitoring
Even with the best preventative measures in place, your team has to monitor for attacks that might slip through the cracks. You’ll want to:
- Look out for spikes in failed logins, especially from unauthorized or multiple locations
- Track traffic from proxy or bot networks, and consider blocking proxy network access altogether
- Regularly monitor data breaches for compromised usernames and passwords
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