What is credential stuffing?

Credential stuffing is a type of cyberattack where stolen usernames and passwords are used to gain unauthorized access to multiple websites, exploiting the common practice of password reuse to carry out fraudulent activities. With 78% of users recycling the same password across multiple sites, credential stuffing is a threat to every organization with online accounts.

How does credential stuffing work?

To carry out a credential stuffing cyberattack, hackers use stolen login credentials to attempt access to different sites, employing tools like botnets and IP rotation to avoid detection. Once logged in, attackers can initiate an account takeover, turning a single stolen credential into a much larger threat.

Here's a detailed look at how credential stuffing works:

• Initial data aggregation: Hackers gather lists of usernames and passwords stolen in data breaches or buy them from criminal sites on the dark web. Stolen password lists can contain hundreds of millions of usernames and passwords, and are often available to bad actors for a relatively small sum.

• Credential validation infrastructure: At this stage, the cybercriminals use special computer programs called bots to try logging into many websites simultaneously. These automated programs can test thousands of passwords every minute. To make attacks more effective, fraudsters can instruct multiple compromised computers to work together in a botnet.

• Proxy and IP rotation mechanisms: Attackers use special tools to hide where the attacks come from by changing network addresses. Multiple fake locations help mask the real source of the attack even more effectively and avoid getting caught by security systems.

• Advanced bot technologies: AI bots are new hacking tools that are very good at imitating real people online. These programs even add random delays and mouse movements to fool security systems. 

• Geographical distribution strategies: Hackers launch attacks from different countries worldwide to prevent suspicion. Login attempts come from places like Europe, Asia, and America simultaneously. Spreading attacks across the globe makes them harder to stop.

• Protocol exploitation: Attackers look for weak spots in how websites handle logins and passwords. Problems with password reset options give hackers more ways to break in. Old or poorly set up security makes a successful attack more likely.

Why is credential stuffing a threat to your business?

When bad actors use credential stuffing to access and control your users’ accounts, they can very rapidly damage your finances, tarnish your brand's reputation, and reduce customer trust. Let’s take a detailed look at how this form of attack can affect your business: 

• Financial implications: Successful credential stuffing attacks allow criminals to make illegal purchases and transactions with the accounts of other users. These customer losses must often be reimbursed by the business providing the compromised accounts. The burden of supporting affected customers, investigating incidents, and taking steps to prevent future breaches can also be substantial—IBM established that each data breach costs companies an average of $4.24 million.

• Reputation destruction: If a credential stuffing attack exposes customer information or causes financial harm, customers will lose faith in your company, potentially driving them towards your competitors. Most customers say they would stop doing business with a company that suffered a data breach exposing sensitive or financial information.

• Regulatory compliance risks: Regulators punish organizations that fail to prevent credential stuffing, and fines for violations often reach millions of dollars per incident. For instance, Geico was fined $9.75 million when a credential stuffing attack allowed unauthorized access to sensitive customer information. 

Top 10 recommendations for how to prevent credential stuffing

Stopping these kinds of digital attacks before they happen requires strategic planning, proactive measures, and the right tools to block hackers before they strike. Combining multiple layers of defense is far more cost-effective than addressing each weakness highlighted by an attack.

Here are ten ways you can combat credential-stuffing attacks: 

1. Advanced multifactor authentication

Adding a second login step, like an OTP code sent to a phone, can block unauthorized access even when a bad actor has obtained a stolen password. 

2. Behavioral biometric integration

 Context-aware authentication software can further enhance protection by analyzing user behavior and interaction patterns, such as how users swipe screens or type. Checking these unique patterns blocks fake logins, even with the right password. 

3. Zero-trust architecture implementation

Implement security systems that require users to prove their identity with every login attempt. Assuming no inherent trust stops breaches before they start, ensuring that only verified users can access sensitive data.  

4. Adaptive rate limiting

Use intelligent software that detects too-rapid login attempts from bot networks. Slowing down logins when this happens allows time to investigate and stop attacks. This sort of rate limiting keeps out credential stuffing bots but doesn't interfere with real users.  

5. Advanced bot detection technologies

Deploy machine learning tools to differentiate between human logins and automated bot activity patterns. Blocking simulated logins helps prevent large-scale stuffing campaigns from even getting started. 

6. Passwordless authentication strategies

Adopt passwordless authentication methods like WebAuthn that rely on cryptographic keys tied to specific devices. These strategies eliminate the risks associated with traditional passwords, rendering stolen credentials useless. 

7. Automated credential rotation

Ensure login credentials are regularly updated by using automated systems that force resets when potential compromises are detected. This prevents attackers from reusing passwords and reduces the risk of breaches caused by human error.   

8. Threat intelligence integration

Staying updated on emerging exploits ensures your security continues to be effective in the face of new threats. Key resources include CERT/CC, SecurityFocus, and the National Vulnerability Database, which provide searchable and sortable information. For in-depth security news and threat intelligence, follow sources like SANS Internet Storm Center, CERT-EU.

9. Honeypot and deception technology

Set up decoy systems to divert attackers from real assets. Honeypots not only protect your systems, they also help you refine your security strategies by gathering valuable data on hacking techniques.

10. Continuous penetration testing

Engage ethical hackers to carry out regular penetration testing to thoroughly test your system's defenses. They can identify and analyze vulnerabilities and offer advice on how to strengthen your security measures.

Use Fastly for the strongest protection against credential stuffing

As attackers continually upgrade their methods, staying ahead of online threats like credential stuffing demands ongoing learning, 24/7 vigilance, and regular updates to your security tools. While there’s no magic bullet, adopting a comprehensive multi-layered approach is essential. 

Fastly offers a bot management service designed to detect and block harmful bot traffic used in cyberattacks like credential stuffing. 

Some of the bot management tool's benefits include: 

• Automatic bot detection: Fastly quickly distinguishes real users from bots. Before blocking, the system double-checks to avoid mistakes that may frustrate genuine users.  

• Real-time threat classification: Because Fastly identifies threats right when they happen, you can act immediately to stop attacks. 

• Interactive and non-interactive challenges: The solution includes tests like CAPTCHAs that help block bots but allow real people to access your site.

• Rate limiting: This feature slows down suspicious login attempts. By limiting requests from questionable sources, Fastly protects your servers from crashing.

• Advanced visibility: By providing in-depth stats, Fastly allows you to investigate attacks. A deep analysis shows which bots have been blocked lately, so you can understand trends more clearly.

• Customizable solutions: Fastly tailors bot management to match what your business needs and allows you to create unique defense plans for your business. 

• Edge protection: With Fastly, threats are stopped directly at the network edge, reducing latency and improving security across your infrastructure.

Do you want to see how Fastly's bot management solution can protect your business? Request a demo today.