Credential stuffing vs. brute force attacks: Key differences and how to stop them

Attacks on digital platforms become more sophisticated every day. Among the most common types of attacks are credential stuffing and brute force attacks. While both methods aim to breach systems by gaining unauthorized access, they employ distinct techniques and strategies. Understanding the differences between these attacks can help individuals and organizations take proactive measures to protect sensitive data and maintain cybersecurity.

What is credential stuffing?

Credential stuffing is a cyber attack method in which attackers use previously stolen usernames and passwords to try to gain access to multiple accounts on different websites or platforms. This attack is so effective because many people reuse the same username and password combination across multiple websites.

Credential stuffing works by automating the login process. Attackers will use specialized software or bots to input these stolen credentials into various platforms, hoping that some of them will match an existing account.

This is how this attack works:

1. Cybercriminals acquire large sets of usernames and passwords from previous data breaches or leaks, often found on dark web forums or underground markets.
2. Using automated bots, the attacker programs them to log into various websites with these stolen credentials.
3. If a user has reused the same login information across multiple sites, the bot may successfully gain access to that user’s account on one or more platforms.
4. Once access is granted, the attacker can misuse the account by accessing personal data, making fraudulent transactions, or using it for further attacks (e.g., account takeover).

Credential stuffing is dangerous because of its high success rate (many users recycle passwords across different sites), its scalability (automated bots allow attackers to target thousands of accounts in a short time), and its low cost.

What is a brute force attack?

A brute force attack involves systematically attempting every possible combination of characters to break a password or encryption key. This type of attack has been around for as long as computer systems and encryption protocols have existed. The fundamental principle behind brute force—systematically trying every possible combination to crack a password or encryption key—remains the same, but the methods and technology used to execute these attacks have evolved significantly over time.

Unlike credential stuffing, which relies on stolen credentials, a brute force attack attempts to guess the correct password by testing various combinations until the right one is found.

Brute force attacks can be conducted against both login systems and encryption protocols. In the case of password-protected accounts, a hacker will try every possible password, starting from simple ones and moving to more complex combinations. Modern attackers may use powerful computing systems or distributed networks (botnets) to speed up the process. This shift in attack tactics took brute force attacks from something that could be executed from a single machine to an attack strategy leveraging the computing power of thousands or even millions of machines.

This is how brute force attacks work:

1. First, the attacker identifies a target system (e.g., an online account or server) and prepares a list of possible passwords (this could be all combinations of letters, numbers, and symbols).
2. Using automated tools, the attacker begins entering different password combinations in an attempt to gain access to the account.
3. After numerous attempts, the attacker eventually finds the correct password and gains access to the account or system.

Brute force attacks are dangerous because it’s effective on weak or simple passwords, and while it can be time-consuming, modern tools and high computing power can reduce the time it takes to crack passwords.

How botnets speed up brute force attacks

A botnet is a network of compromised devices (often computers, IoT devices, or even smartphones) infected with malware and can be remotely controlled by an attacker. These devices can be used to execute coordinated attacks.

A botnet can use thousands or even millions of devices to perform brute force attacks in parallel. Each device in the botnet can attempt a different password combination at the same time. The combined processing power of all the devices drastically reduces the time required to crack a password. Many of these devices may be low-power machines or IoT devices that would otherwise be idle.

Spreading the attempts across multiple devices and using different IP addresses helps evade rate-limiting defenses such as CAPTCHA and account lockouts, making it much harder for the targeted system to detect the attack.

‍How to defend against these attacks

Both credential stuffing and brute force attacks can be mitigated with proper security measures. Here are some of them:

• Use Multi-Factor Authentication (MFA): MFA adds an additional layer of security by requiring users to provide two or more forms of identification.
• Enforce strong password policies: Encourage or require the use of complex, unique passwords that are difficult to guess or crack.
• Implement CAPTCHA: CAPTCHA challenges can help distinguish between human users and automated bots, slowing down both brute force and credential stuffing attacks.
• Monitor and limit login attempts: Systems can be configured to lock accounts or trigger alerts after a certain number of failed login attempts, blocking or delaying brute force and credential stuffing attacks.
• Educate users: Encourage users not to reuse passwords across different accounts and to regularly update them.
• Use account lockout mechanisms: Temporarily locking accounts after multiple failed login attempts can prevent automated attacks from succeeding.
• Monitor for unusual activity: By tracking login attempts, unusual access patterns, and sudden spikes in activity, organizations can detect and mitigate brute force attacks quickly. Behavioral analytics, geolocation-based blocking, and Web Application Firewalls (WAFs), they can all help detect and prevent attack patterns.

For the best protection against these and several other attacks, you should consider using a product that specializes in protecting apps from bots, frauds, and abuse.

WorkOS Radar can help you defend against both credential stuffing and brute force attacks by providing powerful security features, such as risk-based authentication and advanced anomaly detection. Here are some important features:

• Anomaly detection and risk-based authentication: Radar uses sophisticated anomaly detection to identify patterns that may indicate a credential stuffing attack. For example, it can detect unusual login behavior, such as a high volume of login attempts from a single IP address or a set of IPs in a short time frame, multiple failed login attempts across various accounts from a single user or device, and logins from unusual geographies or IP addresses, particularly if the behavior is inconsistent with a user’s normal login patterns. Once these anomalies are detected, Radar can trigger risk-based authentication steps, such as requiring additional verification (e.g., multi-factor authentication), alert the admins, or block access entirely from suspicious locations or devices.
• Intelligent rate-limiting using device fingerprinting: Instead of focusing solely on IP addresses, WorkOS Radar also identifies clients through device fingerprinting. This way you can apply progressive rate limiting that becomes stricter as suspicious behavior continues. These limits apply to the device fingerprint, not just the IP address. This means an attacker can't reset their limit by simply switching IPs. The system tracks:
  
  • Authentication frequency per client.
  • Pattern matching across multiple accounts.
  • Password variation patterns.
  • Geographic distribution of attempts.
• Bot detection: Radar uses bot detection algorithms to identify and block automated attacks. If the system detects that login attempts are being made using bots (rather than legitimate human users), it can block or challenge these requests, preventing them from gaining access to accounts. This bot detection goes beyond simple pattern matching. It can differentiate between AI agents, search engine crawlers, automation scripts, and testing tools.
• Stale accounts: WorkOS Radar monitors dormant accounts (no successful logins in 30+ days) and can notify both the end-user and the administrators when they become active (i.e. login successfully) - a common indicator of account takeover.
• User behavior analytics: By analyzing user behavior patterns (e.g., login times, locations, device types, etc.), Radar can identify any deviations from normal behavior. If an attacker tries to use stolen credentials to log in from an unusual device or location, the system can flag the activity and require further verification steps before granting access.
• Adaptive authentication and device fingerprinting: If Radar detects that a user is logging in from a new device or location after a series of failed login attempts, it may apply adaptive authentication policies. This may involve checking the user’s device fingerprint (such as the browser, operating system, and device details) and verifying that it matches previously used devices. If the fingerprint does not match or seems suspicious, Radar can require additional verification steps, preventing attackers from bypassing security measures through brute force.
• Impossible travel: The physical world has constraints on how fast things can move around. Would you expect that your users can travel faster than the speed of light? Neither does Radar. By tracking device geolocation, Radar can block or alert when subsequent authentication requests are spread around the globe.

For more options and details, see Defending against bad actors.

Conclusion

While credential stuffing and brute force attacks are both common methods for gaining unauthorized access to accounts, they differ significantly in their approach. Credential stuffing exploits the common habit of password reuse, whereas brute force attacks focus on systematically guessing passwords.

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Both attacks can have devastating consequences for users and organizations, but with strong password practices, multi-factor authentication, and other preventative measures, the risk of these attacks can be minimized.

For maximum security you should consider using a product that specialize in identifying and preventing attacks.