Credential stuffing is a type of cyberattack whereby a cybercriminal uses stolen username and password combinations to attempt to fraudulently log into a user’s account. These stolen credentials are obtained through data breaches and sold to other attackers.

As 65 percent of people reuse the same password on multiple (and sometimes all accounts), it is not hard to see why credential stuffing is one of the most common causes of data breaches.

Plus, as more credentials are being exposed via data breaches, the use of credential stuffing amongst cybercriminals is only growing.

However, with the right cybersecurity measures in place, you can prevent credential stuffing attacks from happening. In this guide, we will reveal everything you need to know about the preventive measures you can take to stop credential stuffing attacks from impacting your business.

How a credential stuffing attack works

Attackers utilize bots to conduct credential stuffing because of their scale. Data breaches reveal a massive amount of credentials, and there is no guarantee that those combinations are reused on any other site. This is why attackers leverage automation to launch their attacks at scale. Bots allow operators to test credentials quickly and efficiently. Without the use of automation credential stuffing attacks would not be viable. Although bots make these attacks possible, it also makes them detectable if you are using a modern bot management solution.

Before we take you through some of the different steps you can take to prevent such an attack, it is vital to outline the typical steps these attacks follow:

  1. A bot will be set up that logs into multiple user accounts simultaneously and automatically. Credential stuffing tools are used to fake a number of IP addresses, simulating typical web application traffic and evading browser and IP blocking methods.
  2. Next, the software will check to see whether or not the credentials work on different websites. This is something that is done in parallel and automatically so that repeated logins are avoided.
  3. Many different types of data are gathered from successful logins, including personally identifiable information (PII) and credit cards.
  4. The account information will be recorded for unauthorized use in the future, including large-scale data breaches and phishing attacks.

Such bots can be damaging, which is why it is critical to understand how to prevent credential stuffing attacks.

With that in mind, let’s take a look at some of the different things you can do to protect yourself from the sophisticated techniques attackers use:

Implement cryptographic challenges

Were you told that CAPTCHA challenges were a good choice for preventing credential stuffing attacks? Think again! CAPTCHA is not sufficient, and most threat actors today can bypass this with relative ease.

Instead, you need to make bots do the work, not humans – which is what CAPTCHA does.

With cryptographic challenges, you can cleverly deter synthetic traffic, by making attacks expensive and arduous for bots to continue their attacks while remaining imperceptible to and demanding no action from the end-user.


Screen for leaked credentials

Adopt solutions that can scan for a user’s account logins automatically against a substantial database of compromised credentials that have been published on the dark web.

This way, you can immediately alert your users if part of their credentials matches those in the database at present. Allowing them to change their password on your site.

It is worth noting that this sort of screening is an effective tool but it is only going to work if the database that was breached has been published on the Internet. If compromised credentials were not published or have been privately sold, this will not be detected. This solution is also only effective if your users take action to change their passwords, allowing bot operators to successfully continue their attack until the password is updated, if it ever is.

Look for immutable evidence of automation

The issue with a lot of solutions today is that they rely on contextual data from the past, rather than looking for real-time evidence.

While historical data is an important piece to stopping bad actors, it cannot properly defend your site from credential stuffing attacks. This data can only defend attacks that have been detected before. Failing to keep pace with new methods of attacks that bot operators are continuously working on. Allowing new attacks to fly under the radar and access your infrastructure.

Instead, solutions like Kasada will search for immutable evidence of automation that exist from the tools that are used to conduct threats at-scale (e.g. Headless Chrome, customized Puppeteer, Playwright) , from the very first request. This approach allows the solution to quickly detect and mitigate malicious requests from the first page load.

Robot and Machine Learning

Invest in a bot detection system

Another way to keep your business protected from a large-scale credential stuffing attack is to invest in a bot detection and management solution, like Kasada. A modern anti-bot solution will be able to effectively detect malicious bot traffic and block it in real-time from attempting an attack.

As it becomes more complicated to tell humans and bots apart using traditional methods like device fingerprinting, a new approach that utilizes automation to defend against credential stuffing attacks in real-time has become a necessity. Humans simply are unable to act quickly enough to contend with bots, which is why modern bot detection solutions that fight automation with automation can be incredibly effective in stopping credential stuffing attacks from taking place.

Consider passwordless authentication

Once attackers break in, they can also prevent customers from getting access to their own resources.

Having passwords as an authentication factor can leave business and consumer accounts vulnerable to credential stuffing, so you may want to consider removing them altogether.

You can use passwordless authentication as a safe and effective way of authenticating users for more confined account access.

How does Kasada work to prevent credential stuffing?

Kasada leverages proprietary techniques to present a myriad of obstacles that will disrupt and frustrate bot attacks. This will challenge vital elements of the attack process, as well as stopping threat actors from utilizing automation.

When a bot attempts to imitate a human user, it will leave automation traces within your environment. With our advanced invisible interrogation process, we can detect these traces and use telemetry in our decision engine to detect these attacks and prevent them from happening.

Bots are detected immediately, and they are then grouped as either malicious or benign. This process does not require CAPTCHAS and is fully invisible to a normal user, meaning customers will have a frictionless journey.

We also implement a cryptographic challenge, which forces malicious requests to solve an increasingly difficult asymmetric cryptographic challenge as a proof of work. This exhausts adversaries’ CPU resources without alerting them. Resulting in high costs for the attack with nothing to show for it, deterring future attacks and reserve engineering attempts.

Final words on preventing credential stuffing attacks

We hope that the steps that we have mentioned above help you to get a better understanding of the different options that are available to you when it comes to preventing credential stuffing attacks.

From searching for automation evidence to implementing cryptographic challenges, there are a number of things you can do to reduce the chances of becoming a victim of credential stuffing. It is important to take this seriously, as it is one of the rifest forms of data breaches at the moment.

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