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Credential Stuffing Attacks

Credential stuffing is one of the most prevalent cyberthreats of 2024. This attack method uses stolen usernames and passwords to gain unauthorized access to online accounts and cybercriminals often leverage automation to test millions of credential combinations across multiple sites.

The Ticketmaster breach in June 2024, which compromised 560 million customer records, highlights the growing severity of credential stuffing attacks. This guide explains the mechanics of credential stuffing and offers strategies to defend against this growing threat.

1. What is Credential Stuffing?

At its core, credential stuffing exploits users’ habit of reusing passwords across multiple services. Once cybercriminals obtain stolen login credentials—whether through a data breach, phishing attack, or from password dump sites—these details are added to a database. Attackers then use bots and automated scripts to test the stolen credentials on different websites until they find a successful match. According to OWASP, credential stuffing usually begins by sourcing login details from breaches and then systematically testing them across multiple platforms.

Credential Stuffing Diagram

These attacks can have a devastating impact on both individuals and organizations. For individuals, successful credential stuffing attempts can lead to financial loss, identity theft, and personal data exposure. For organizations, the consequences can be even more severe—financial fraud, reputational damage, and loss of consumer trust.

2. Examples of Credential Stuffing Attacks

Several high-profile companies have fallen victim to credential stuffing attacks, highlighting the importance of robust security measures:

  • Disney+ (2019): Just hours after the platform’s launch, hackers used stolen credentials to gain unauthorized access to thousands of user accounts. These credentials were quickly listed for sale on the dark web.
  • DraftKings (2022): A credential stuffing attack on DraftKings led to the theft of $300,000 and compromised the accounts of 67,000 users.
  • PayPal and 23andMe (2023): Both companies faced significant credential stuffing attacks, with sensitive user information being exposed.
  • Okta (2024): The authentication service provider, warned users about an increase in credential stuffing incidents targeting its platform
  • Roku (2024): Roku experienced a large-scale attack affecting 591,000 accounts.

3. Why Credential Stuffing is So Dangerous

Credential stuffing presents a unique threat because it can be automated and the large-scale nature of attacks:

  • Automation: Cybercriminals use automated tools to rapidly test stolen credentials across multiple websites. These bots can test millions of username-password combinations in a matter of hours.
  • Reused Credentials: Many people reuse passwords across different services. This allows attackers to use credentials from a single breach to access multiple accounts, exponentially increasing the damage.
  • Difficulty Detecting Attacks: Credential stuffing often resembles legitimate login attempts, making it difficult for traditional security systems to differentiate between real users and attackers.

4. How to Prevent Credential Stuffing Attacks

Organizations can take several proactive steps to defend against credential stuffing:

  • Encourage Strong, Unique Passwords: The first line of defense against credential stuffing is encouraging users to create strong, unique passwords for each account. This reduces the risk of one breach compromising multiple accounts.
  • Multi-Factor Authentication (MFA): Implementing MFA adds an extra layer of security by requiring additional forms of verification beyond just a password. According to research from Microsoft, MFA is 99.9% effective at preventing credential stuffing attacks.
    • MFA Types: MFA relies on three types of factors:
      • Knowledge Factors (e.g., security questions)
      • Possession Factors (e.g., badges, keys, or mobile devices)
      • Inherence Factors (e.g., biometric data like fingerprints) Even if attackers obtain valid credentials, MFA makes it significantly harder for them to gain access to an account.
  • Rate Limiting: Organizations can use rate limiting to control the number of login attempts allowed within a specific timeframe. This disrupts automated tools by slowing down the process, giving security teams more time to react.
  • Monitoring for Compromised Credentials: Automated baselines of normal user behavior can help security teams detect and respond to anomalies. Tools like Devo SOAR can be used to identify potentially compromised credentials and alert appropriate personnel for response.

5. Conclusion

In today’s threat landscape, credential stuffing attacks are on the rise, fueled by automation and the increasing availability of stolen credentials. The ease with which cybercriminals can launch these attacks makes them a serious risk for both individuals and organizations. To defend against this growing threat, security teams must adopt a multi-faceted approach, including enforcing strong password policies, implementing multi-factor authentication, and monitoring for compromised credentials.

By staying vigilant and proactive, organizations can mitigate the impact of credential stuffing and protect their users from unauthorized access and data breaches.





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