Imagine a hacker using a database of stolen usernames and passwords from a past data breach to access multiple accounts across different platforms. This is a credential stuffing attack which is a tactic where attackers exploit reused login credentials to gain unauthorized access to sensitive accounts, leading to vendor fraud, data breaches, and reputational damage.
With cyber threats on the rise, businesses must take proactive steps to secure their accounts. Trustpair helps companies prevent fraud by ensuring secure financial transactions and account verification, reducing the risk of unauthorized access and credential-based attacks.
Read our latest fraud study to discover fraud trends and expert insights to protect your business against cyber fraud.
What is a Credential Stuffing Attack?
Credential stuffing is a type of cyberattack where hackers use stolen username-password combinations to gain unauthorized access to online accounts. Unlike traditional hacking methods that attempt to guess passwords, credential stuffing relies on automation, with attackers using bots to test stolen credentials across multiple platforms.
Since many users reuse passwords across different accounts, this technique has a high success rate. Once an attacker gains access, they can steal sensitive information, make fraudulent transactions, or sell account details to other cybercriminals. These attacks pose a significant threat to both individuals and businesses, leading to financial losses, data breaches, and reputational damage.
This type of attack is highly effective because many users reuse passwords, making it easy for hackers to take over multiple accounts with minimal effort. In 2021, Roku, a major streaming service suffered a credential-stuffing attack that compromised thousands of accounts, leading to unauthorized purchases and data leaks. Since attackers use legitimate credentials, their activity often bypasses security measures, making detection difficult.
How Credential Stuffing Works
Credential stuffing attacks take advantage of stolen login credentials and automation to break into user accounts. Here’s a step-by-step breakdown of how attackers execute these attacks:
- Data breach exposure – Hackers obtain millions of usernames and passwords from previous data breaches. These credentials are often sold or leaked on the dark web.
- Automated credential testing – Attackers use bots or scripts to systematically test stolen credentials across multiple websites and applications.
- Successful logins – If a user has reused their password on different accounts, the attacker gains access without needing to crack the password.
- Account exploitation – Once inside, attackers can steal personal data, make unauthorized transactions, or sell access to other criminals.
- Scaling the attack – If login success rates are high, hackers may launch further attacks, such as synthetic identity fraud, financial theft, or ransomware deployment.
Because these attacks rely on automation and real login credentials, they can bypass security measures like basic password protections and CAPTCHAs, making them a persistent and dangerous threat.
Credential Stuffing vs. Brute Force Attacks
While credential stuffing and brute force attacks both target user accounts, they use different methods to break in. To prevent account takeover, understanding the differences is key to recognizing and preventing these threats.
Credential Stuffing Attack
- Method: Uses stolen username-password pairs from past data breaches.
- Automation: Attackers deploy bots to test credentials across multiple websites.
- Success rate: High, since many users reuse passwords.
- Detection difficulty: Harder to detect because attackers use real login credentials.
- Example: A hacker obtains leaked passwords from a breached e-commerce site and successfully accesses users’ bank accounts because they used the same login details.
Brute Force Attack
- Method: Systematically guesses passwords by trying all possible combinations.
- Automation: Uses software to rapidly test different password variations.
- Success rate: Lower, as strong passwords take longer to crack.
- Detection difficulty: Easier to spot due to high volumes of failed login attempts.
- Example: An attacker uses a program to repeatedly guess a user’s banking password, cycling through thousands of common or weak passwords until they find the right one.
While brute force attacks rely on password cracking, credential stuffing exploits human behavior – specifically, password reuse. That’s why enforcing unique passwords and multi-factor authentication is crucial for defense.
Why Credential Stuffing is on the Rise
Credential stuffing attacks have become increasingly common, posing a serious threat to businesses and individuals alike. Several key factors contribute to this rise:
Widespread password reuse
Many users reuse passwords across multiple accounts, making credential stuffing highly effective. If one account is compromised in a data breach, attackers can use the same credentials to access other platforms, including banking, email, and corporate systems.
Advanced automation & bots
Hackers now use sophisticated bots and scripts to test thousands of credentials per second. These tools can bypass basic security measures like CAPTCHA and allow attackers to scale their attacks efficiently.
Weak security measures
Many companies still rely on password-based authentication alone, without enforcing additional layers of security like multi-factor authentication (MFA) or bot detection. This lack of protection makes credential stuffing easier for cybercriminals.
Financial gains for hackers
Compromised accounts can be monetized in various ways, from stealing funds and making fraudulent transactions to selling account access on underground forums. Some attackers even use stolen credentials to launch further cyberattacks, such as phishing or ransomware.
How to Detect and Prevent Credential Stuffing
Credential stuffing attacks can be difficult to detect, as hackers use real login credentials to bypass security systems. However, businesses and individuals can take proactive steps to identify and prevent these attacks.
Detecting Credential Stuffing Attacks
- Unusual login activity – A high number of failed login attempts from different locations or devices may indicate an ongoing attack.
- Traffic spikes – An abnormal surge in login requests, especially from bots, suggests automated credential stuffing.
- Increased account takeovers – A rise in users reporting unauthorized access is a strong sign of credential stuffing attempts.
- Consistent login failures for many users – If multiple users experience login issues simultaneously, it could mean their credentials are being tested by attackers.
Preventing Credential Stuffing Attacks
- Enforce Multi-Factor Authentication (MFA) – MFA adds an extra layer of security, requiring users to verify their identity beyond just a password.
- Implement bot detection tools – Use rate limiting, CAPTCHA, and bot management solutions to block automated login attempts.
- Encourage unique passwords – Educate users about password hygiene, encouraging them to use unique passwords for each account.
- Monitor for compromised credentials – Regularly check databases of leaked credentials to prevent attackers from using stolen passwords.
- Use behavioral analysis – Advanced security tools can flag suspicious login patterns, such as access attempts from unusual locations or devices.
- Enable account lockouts – Temporarily locking an account after multiple failed login attempts can help disrupt credential-stuffing efforts.
To conclude
By combining strong authentication methods, real-time monitoring, and user awareness, organizations can significantly reduce the risk of credential-stuffing attacks and protect sensitive data from cybercriminals.
Trustpair prevents fraud by securing transactions and verifying third-party data in real time, stopping credential stuffing risks before they cause harm. Contact an expert to learn more!
