What is Credential Stuffing? Examples & Prevention

Credential stuffing is an emerging type of cyber threat that takes advantage of a commonly exhibited user behavior: using the same password on numerous online accounts. Cybercriminals take advantage of credential stuffing vulnerability by using stolen username and password combinations often attained from previous breaches, and they automatically attempt logins on a massive scale across multiple platforms and services. While the attack may differ from others in the fact that it does not involve sophisticated techniques as used by hackers in getting into systems, credential stuffing benefits from the simplicity of the human error-mostly, users failing to come up with unique, secure passwords for each account they own.

The attack, however, has left shivers running down most business spines across industries. The worst hit are those that have managed sensitive information of customers or financial transactions. A successful credential stuffing could prove to be a lethal blow to any business. For businesses, the impact is multifaceted: they can face significant financial losses due to fraud or unauthorized transactions, incur costly reputational damage as trust in their brand erodes, and potentially be subject to legal and regulatory penalties if they fail to safeguard user data according to data protection laws, such as the General Data Protection Regulation (GDPR) or California Consumer Privacy Act (CCPA). In fact, in 2018 and 2019, the combined threats of phishing and credential stuffing made up roughly half of all publicly disclosed breaches in the United States.

In this article, we delve deeper into all details of credential stuffing, understanding how it works, differences from similar types of attacks, and steps related to its detection, prevention, and response.

What is Credential Stuffing?

Credential stuffing is an attack in which the attackers use stolen credentials, usernames, and password pairs, obtained from one platform to gain unauthorized access to accounts on another platform. Since many users reuse the same credentials across several sites, this becomes highly effective for cyber thieves.

Attackers typically run these with scripts or bots to push tens of millions of login attempts to thousands of different sites. Once an attacker can gain access to an account, they can then use it for further nefarious activities, such as identity theft or fraud, or even trade the account’s credentials on the dark web.

Credential Stuffing vs Brute Force Attacks

While both credential stuffing and brute-force attacks fall in the category of cyberattack, they actually span over the same issue: unauthorized login attempts to user accounts. However, the difference between the approaches of these two methods, though very similar at first glance, lies in the implementation of each.

• Credential Stuffing: Credential stuffing is a large-scale attack. Here, cybercriminals steal the usernames and passwords grabbed in previous data breaches. These are usually on sale on the dark web or traded within hacker forums. Attackers will try these login combinations with automation tools like bots over various sites and services hoping that users have used the same credentials for other sites, and in most cases, people reuse their passwords for various applications. Most people tend to keep the same passwords for different applications, and thus attackers can easily access accounts by getting through password reusability, with little work on their part. In this aspect, credential stuffing is essentially quantity over quality, because it relies on phishing for poor password hygiene and simply trying to crack as many accounts as possible.
• Brute Force Attack: Compared to this, the brute force attack is more focused and laborious. The attackers do not rely on stolen credentials; instead, they try to guess the user’s password by attempting different letter-number-symbol combinations until getting the right one. This can be done either by hand or, more commonly, using automated tools that spit out hundreds of password possibilities quickly. Brute force attacks hit one account, not hundreds, thereby making them somewhat less efficient at cracking a large breach. In addition, due to the numerous failure attempts, it is likely that the attack will be caught sooner rather than later, in much the same way a CAPTCHA screen or an account lockout would prevent the attacker from cracking the account.

Impact of Credential Stuffing on Businesses

Credential stuffing can cause extremely damaging impacts on businesses by bringing about a holistic array of consequences related to financial stability, customer trust, and compliance with rules.

• Monetary loss: The most apparent impact is monetary loss. Successful credential-stuffing attacks lead to fraudulent transactions, data theft, and fraud. The business also suffers significant losses in the form of mitigation costs, as they need to reimburse the affected customers, trace the breaches through proper investigations, and implement some level of security improvements. It may reflect millions of dollars for a big organization within a very short period of time.
• Reputation damage: Credential stuffing breaches cause the erosion of customer trust. With any breach, news travels fast, and customers lose faith that the company will protect personal information. It can lead to customer churn, wreck brand loyalty, and negate efforts to attract new customers, and all these are long-term consequences for businesses.
• Operational disruption: Operational disruption is another critical concern. A credential stuffing attack often involves redirecting the company’s core competencies from its business to management and investigational work. This translates to downtime, increased operational expenses, and pressure on customer services, which answer questions and resolve issues for impacted users. The need to strengthen security and fix holes also can cause short periods of slowdowns in business processes.

Common Targets of Credential Stuffing Attacks

Some industries are targeted because the value of data, to which access has been gained, is high, and the attacker can easily monetize it.

Here are some of the most common targets for these types of attacks:

• Financial Institutions: One of the most attractive areas of attack on financial institutions is credential stuffing. Online banking sites, payment processors, and fintech services hold sensitive financial information; therefore, the incentive to attack these targets is very high for attackers. Once cybercriminals gain access to an account, they can steal money, make unauthorized transactions, or sell those accounts to other criminals. Since the direct possibility of theft into financial accounts exists, financial institutions are often targeted, and credential stuffing often acts as a precursor for major financial fraud.
• E-commerce sites: The other most targeted area is online stores or e-commerce websites. Attackers target online retailers to gain access to customers’ accounts containing information about payments, shipping details, or stored credit card numbers. Once they get hold of it, attackers can make unauthorized purchases, steal loyalty points, or change account details to further the fraudulent practice. The fact that e-commerce platforms are filled with potential, exploitable user accounts makes them more vulnerable to credential-stuffing attacks.
• Social media platforms: Often, social media accounts are targeted. The attackers, after breaching a social media account, steal personal information and further use the account in order to spread malware, phishing links, or other malicious content. An attacker may continue impersonating the owner of the account, convincing contacts to hand over sensitive information or become victims of certain scams, after gaining access to a social media account. Indeed, due to the sphere of popularity of social media around the globe, a successful attack of credentials stuffing might have some serious consequences.

How Does Credential Stuffing Work?

Credential stuffing is a form of systematic, automated cyberattack that exploits the use of compromised login credentials across multiple platforms. The attack typically unfolds in a series of steps, with attackers leveraging readily available tools and resources to execute large-scale login attempts.

Here’s how credential stuffing usually works:

1. Acquisition of Credentials:  In a credential stuffing attack, acquisition of stolen login credentials takes its first move usually as combinations of usernames and passwords. These accounts are usually gotten from other earlier breaches, phishing operations, or purchased on darknet websites. Many of these credentials are leaked in mammoth data leaks, sometimes amounting to millions of account credentials. Through these lists, attackers rely on the sheer possibility that users might have used the same login credentials elsewhere.
2. Automated Login Attempts: Having received these credentials, hackers automatically generate login attempts on a vast list of websites and online-based applications. These bots can carry out thousands of login attempts in seconds by inputting stolen username/pass pairs across a number of services like online banking sites, e-commerce websites, social networking sites, and many others. Automation is key to credential stuffing since it enables attackers to hit multiple accounts in very little time, with the least effort. The idea here is to test as many credentials as possible to find some that match.
3. Successful Logins: If any of the stolen credentials match with one on a different platform, the attacker gains unauthorized access to the account. It is the basic step where credential stuffing deviates from brute force attacks because credential stuffing relies on valid login credentials whereas the brute force attack tries random password combinations. Since most people use the same password to access different platforms and large volumes of credentials are tested, the chances of finding a match are relatively high.
4. Further Exploitation: Once the attacker has logged in with the reused account, there are several ways that the compromised account could be exploited. Depending on the type of account compromised, they could steal sensitive private information, financial information, or payment information. For an e-commerce platform, they would commit unauthorized purchases or transfers. Furthermore, hackers would sell access to these compromised accounts or simply employ them to carry out further attacks such as phishing, spreading malware among others, and credential stuffing attempts. Subscriber accounts may also be resold for subscription services so that other people can use them to consume free paid content.

How to Respond to a Credential Stuffing Incident?

When a credential stuffing attack is detected, swift and decisive action is key to limiting damage and protecting user accounts.

Here’s how to effectively respond:

1. Lock Compromised Accounts: After you’ve found the fact that the account is compromised, the first action would be to lock the compromised accounts. Be sure that compromised users change their passwords right away. Prevent any further exploitation by closing access accounts until a user can identify himself and reset his password.
2. Monitor for Unusual Activity: Monitor changes in account behavior and login activity. Identify red flags such as spikes in login attempts, access by unknown IP addresses, or suspicious transactions. Use automated tools to flag out-of-norm activity to support real-time identification of vulnerabilities.
3. Inform Affected Users: Be transparent. Reach out to all affected users on the compromised accounts in real-time and request them to change all their passwords wherever it has been used elsewhere. Suggest to the user that he should activate MFA, which will prevent further attacks because there is one more layer.
4. Implement Security Enhancements: Add more controls to help strengthen the defenses against attacks. Implement IP blacklisting, in blocking known sources of bad guys; CAPTCHA challenges, in breaking up automated bots; and security monitoring general improvements. Review the login processes and apply rate limiting to stop large-scale automated attacks.

How to Detect Credential Stuffing Attempts?

Early detection of credential stuffing attempts is a key way to limit the damage they can do and involves a combination of advanced technical tools, security protocols, and vigilant monitoring.

Organizations can therefore detect and respond to attempts at credential stuffing by monitoring for these signs and using pertinent security technologies.

Some of the key methods for detecting such attacks include:

• Spike in Failed Logins: The most obvious indicator of credential stuffing is a sudden spike in failed login attempts. Since attackers use stolen credentials across multiple accounts, many of these will not match existing users or even become outdated, causing multiple failed logins. This is also the most critical one to monitor because it often spells an indication that some automated bot is spamming username-password combinations at a very fast rate.
• Unusual Geographic Access Patterns: Credential stuffing attacks often include login attempts from numerous geographic locations in an astonishingly short period of time. To hide their activity, attackers could be using bots located throughout a large number of regions or countries. This creates situations where accounts indicate logins from multiple locations, often unknown to you. Therefore, watch for accounts displaying these kinds of geographic anomalies.
• Increased Use of Bots: The attacks are typically made using automated bots geared to try huge volumes of login attempts in quick succession. Detection of nonhuman activity is crucial for the detection of these attacks. Traffic analysis tools can identify bot-like behavior such as extremely fast login attempts, unusual request patterns, or activity bypassing CAPTCHA challenges. Bot-detection solutions or behavioral analytics can flag abnormal access attempts, giving system administrators ample time to take mitigative measures and block malicious activity before they compromise the accounts.

Credential Stuffing Prevention Best Practices

Businesses are advised to take various forms of security best practices that will strengthen account protection and minimize credential stuffing vulnerability. These measures are set to block automated login attempts, promote good password practices, and add layers of defense.

Some best practices for preventing a credential-stuffing attack include the following:

1. Multi-Factor Authentication (MFA): The most effective defense against credential stuffing attacks is multi-factor authentication (MFA). Multi-factor authentication adds a layer of protection, as an additional form of verification is required beyond just the password, such as entering a one-time code that was sent to the user’s phone, a biometric factor, like fingerprint recognition, or push notification. Even if attackers are able to obtain valid login credentials, they cannot access any of the accounts without a second factor or authentication. It makes it much harder for attackers to compromise user accounts.
2. Rate Limiting: This is a technique whereby the number of log-in attempts that come from one particular IP address or user within a certain time period can be limited. Companies will sharply reduce the effectiveness of these credential-stuffing attacks by limiting the number of log-in attempts that can be made within a very short time frame. Rate limiting slows down attackers and makes the large-scale testing of credentials cumbersome and less efficient.
3. CAPTCHA Challenges: One of the most effective defenses against credential stuffing attacks is to include CAPTCHA challenges in login processes. CAPTCHAs are used to distinguish between humans and bots by requiring the user to solve trivial puzzles and complete tasks that are easy for a human, but difficult for an automated system. This reduces attempts by bots to log into accounts in a repetitive manner, resulting in reduced opportunities for account tampering. CAPTCHAs are even more useful when coupled with rate limiting and other bot-detection technologies.
4. Password Strength Policies: This is necessary to prevent credential stuffing-based attacks. Organizations must have policies that force users to create complex passwords that are difficult to guess or crack. For instance, organizations must require the use of both uppercase and lowercase letters and numbers, special characters. Organization companies must also encourage a frequently changed password so that the user is not using the same password for a series of accounts. Perhaps the single best practice for minimizing account compromise is to educate users on creating robust, unique passwords.
5. Monitoring and Anomaly Detection: There must be continuous monitoring of login attempts and user behavior as the detection and response mechanisms work in real time against credential-stuffing attacks. The anomaly detection system is also useful to flag suspect patterns, such as unusual attempts at logging in large numbers through the same IP address or several failed log-in attempts for one account. Some organizations will use alerts for suspicious activities and notify users of their account accounts being locked and subjected to higher verification processes for some period.

Credential Stuffing Attacks: Real-Life Examples

In this section, we’ll explore real-life credential stuffing attacks along with the methods an attacker used, the impact on the victims, and lessons learned to amplify security measures. One of the most significant is the case of Nintendo which was hit by a significant credential stuffing attack in 2020 and demonstrates the dangers associated with reused credentials, as well as the importance of strong security practices.

• Nintendo: In 2020, Nintendo experienced one of the most damaging credential-stuffing attacks after hackers exploited already-compromised login data and used niche crimeware tools to access thousands of user accounts without permission. However, the actual compromise was about 160,000 accounts, as hackers utilized lists of usernames and passwords that had become public after other breaches. Many of them used one login for their Nintendo Network ID, hence the ease with which attackers succeeded in logging into those accounts.
• Spotify: In the year 2020, Spotify encountered a massive credential-stuffing attack that compromised millions of accounts. Hackers used leaked usernames and passwords from previous data breaches that could illegitimately access the accounts of Spotify users. This was one of the many credential stuffing attacks, in which cybercriminals exploited an all-too-common pattern among many users to reuse the same password on multiple services. Once attackers obtained the leaked credentials, they applied automated tools and bots to attempt to log into Spotify accounts en masse. Most Spotify users reused passwords from other services that were breached and made their accounts vulnerable to takeover.
• The Deliveroo Dilemma: Another food delivery giant Deliveroo too did not remain immune to credential-stuffing attacks. Mysterious transactions were appearing on customer accounts, where several users complained about unfamiliar orders surfacing in multiple locations around the globe. Attackers used these very credentials to break into different user accounts by exploiting the fact that the platform had not enabled multi-factor authentication for safeguarding users’ accounts. The ease with which attackers could breach customers’ accounts led to financial damage and also loss of trust in the brand. It was amid such an event that revealed the necessity to further heighten security measures on these channels, which includes two-factor authentication, to prevent unauthorized access to accounts.
• The Ticketfly Breach:  In 2018, hackers gained access to data of around 27 million Ticketfly accounts after a credential-stuffing attack. They exploited a weakness on the site of its website to gain unauthorized access to thousands of consumer and event organizers’ accounts.  The breach leaked sensitive information to unauthorized people, including user names, email addresses, and hashed passwords. The Ticketfly breach highlights that companies need to review their security measures regularly, patch vulnerabilities, and urge users to practice good password hygiene.

How SentinelOne Can Protect Businesses Against Credential Stuffing?

SentinelOne’s Singularity™ Cloud Native Security platform provides advanced features and capabilities that give complete protection against credential stuffing through advanced features and capabilities. Here are some of the key ways in which SentinelOne can help businesses protect their systems from credential-stuffing threats:

1. Automated Threat Detection and Response: Singularity™ Cloud Native Security uses machine learning algorithms to automatically identify behaviors indicative of credential stuffing attacks. The system uses the patterns associated with this type of attack to provide real-time responses in blocking malicious login attempts before they compromise accounts.
2. Behavioral Analysis: The platform continuously monitors user behavior across the network, allowing it to establish baselines for normal activities. Any deviations from this baseline, such as unusual login attempts or access from unfamiliar locations, are flagged for immediate investigation, helping to quickly identify potential credential stuffing incidents.
3. Integration with Identity Protection Solutions: Singularity™ Cloud Native Security can integrate seamlessly with identity protection solutions as well as multi-factor authentication systems to build a stronger security posture. Using additional verification steps when attempting to access sensitive actions or from new devices or locations reduces the risk of unauthorized access in that area significantly.
4. Threat Intelligence: SentinelOne provides businesses with real-time threat intelligence, which would allow them to identify the latest tactics in credential stuffing and emerging threats. This way, the organizations remain proactive in staying ahead of the cybercrooks who make the necessary adjustments for security.
5. Automated Incident Response: On detection of credential stuffing attacks, Singularity™ Cloud Native Security can auto-apply all the process incident response, isolate affected accounts; initiate password resets; and notify users of suspicious activity, thereby reducing damage and response time.

Conclusion

Credential stuffing is an increasingly burgeoning cyber threat that businesses need to be proactive against so that their operations, customer data, and reputations are secure. Since most cyber attackers are now using stolen login credentials of people from various breaches, companies stand at a heightened risk of account takeovers, financial losses, and operational disruptions. The good news is that their risks can be starkly reduced by embracing strong security practices and leveraging advanced protection solutions such as SentinelOne’s Singularity Cloud Native Security platform.

Understanding how credential stuffing attacks work and how defense mechanisms can be put in place, like MFA, rate limiting, CAPTCHA challenges, and regular security monitoring, may reduce the chance of unauthorized access. With the right technology to back up the effort, businesses can always stay ahead of cyber-criminals and keep their systems, accounts, and data safe.

FAQs

1. How does credential stuffing relate to password spraying?

Credential stuffing and password spraying are two forms of weak password exploitation. However, the strategy involved differs. Credential stuffing makes use of specific stolen usernames and passwords, usually stolen from earlier data breaches, used to log in to several sites with unauthorized access. In contrast, password spraying involves the attacker attempting a small number of commonly used passwords, such as “123456” or “password,” across many accounts to avoid triggering account lockouts. The two rely on weak or reused passwords but in opposite directions.

2. What is the best solution to credential stuffing?

The best response to defeating credential stuffing is a layered approach. MFA adds another layer of protection beyond a password, thereby making it significantly more difficult for attackers to gain access. The CAPTCHA challenges added to passwords to bar bots from mass logins and regular monitoring of login activity help detect suspicious attempts earlier than others. All these put together are the right steps towards prevention.

3. Is credential stuffing a DDoS attack?

Credential stuffing is not a DDoS attack. A DDoS attack attacks a service by sending a vast amount of traffic, stalling, and slowing down the system. The idea behind a credential stuffing attack is to try targeted log-ins using hijacked credentials with the aim of entering unauthorized users rather than breaking services.

4. How to prevent credential stuffing?

Businesses can prevent credential stuffing by executing several key steps. Enabling Multi-Factor Authentication (MFA) adds an extra security layer by directing users to confirm their identity through additional ways. Rate limiting restricts the number of login attempts from a single IP address, while CAPTCHA challenges can help distinguish between human users and bots. Educating users on building strong, unique passwords and enabling password managers also helps prevent password reuse. Finally, monitoring login patterns for unusual activity allows for early detection and response to potential attacks.

5. What are the key signs of a credential stuffing attack?

Key signs of a credential-stuffing attack include:

• Spike in failed login attempts: A significant increase in failed logins over a short period is a common indicator, as attackers test large lists of stolen credentials.
• Logins from unusual geographic locations: Account activity from locations that are far from a user’s usual region, especially multiple locations within a short timeframe, can be a sign of credential stuffing.
• Increased bot traffic: Credential stuffing attacks are often carried out by bots, so unusual patterns of rapid, automated login attempts may signal an attack.