What is a Credential Stuffing Attack?

What is a credential stuffing attack?

A credential stuffing attack is a type of cyber attack where attackers use stolen account credentials (usernames and passwords) to gain unauthorized access to user accounts through large-scale automated login requests. This method relies on the fact that many people reuse the same usernames and passwords across multiple services.

In a credential stuffing attack, the attacker typically obtains a list of compromised credentials from a previous data breach or from the dark web. They then use automated tools to try these credentials on various other websites and services to see where else these credentials might work. Because of the automated nature of the attack, they can test thousands to millions of credential combinations in a very short period.

The success of these attacks often leads to unauthorized access to user accounts, identity theft, financial loss, and other forms of fraud. It’s a significant threat in the digital world, underscoring the importance of using unique passwords for different sites and employing multi-factor authentication wherever possible.

What’s the difference between a credential stuffing attack and a brute force attack?

Credential stuffing attacks and brute force attacks are both methods used by cybercriminals to gain unauthorized access to user accounts, but they differ significantly in their approach and methodology:

1. Credential Stuffing:
   • Pre-Existing Credentials: This method relies on using usernames and passwords that have been previously exposed in other data breaches. The assumption is that many users reuse the same login information across different platforms.
   • Targeted: Credential stuffing attacks specifically target websites where users might have reused their credentials.
   • Automated: These attacks are largely automated, using bots to quickly attempt logins across multiple websites with the stolen credentials.
   • Efficiency: This method is more efficient when the attacker has access to confirmed user credentials, thus having a higher success rate in gaining access without the need to guess combinations.
2. Brute Force Attack:
   • Guessing Credentials: Unlike credential stuffing, brute force attacks involve systematically guessing all possible password combinations until the correct one is found. This can start with the most likely options (like “123456” or “password”) and move to more complex combinations.
   • Broad: These attacks can be directed at any single account or service, without any prior knowledge of valid username and password combinations.
   • Resource-Intensive: Brute force attacks require significant computational power and time, especially as password complexity increases.
   • Low Efficiency: Since brute force attacks involve guessing from scratch, they are generally less efficient and have a lower success rate compared to credential stuffing, where valid credentials are already known.

In essence, credential stuffing attacks exploit users’ habits of password reuse across multiple services using known credentials, while brute force attacks attempt to decode passwords through exhaustive trial and error. Both attacks highlight the need for strong, unique passwords and the implementation of additional security measures like multi-factor authentication (MFA) to safeguard accounts.

What’s an example of a credential stuffing attack?

An example of a credential stuffing attack occurred in 2018 involving the video streaming service Hulu. Here’s a breakdown of how the attack likely unfolded:

1. Acquisition of Credentials: Attackers obtained lists of usernames and passwords from breaches of other companies or sources. These credentials are often sold or shared on dark web marketplaces.
2. Preparation: Using automated tools, the attackers prepared to test these credentials on Hulu’s login system. Such tools can handle thousands of login attempts simultaneously and are designed to mimic legitimate user behavior to avoid detection.
3. Execution: The attackers then launched the credential stuffing attack against Hulu. The automated tools systematically inputted the stolen usernames and passwords to see if they would work on Hulu’s platform.
4. Access and Exploitation: Successful login attempts allowed the attackers to gain unauthorized access to Hulu accounts. They could potentially watch premium content or use the accounts for further malicious activities, such as spamming or phishing.
5. Detection and Response: Once Hulu detected unusual activities, they likely took steps to mitigate the attack. This could include resetting passwords for affected accounts, enhancing security measures, and implementing more robust detection mechanisms to prevent future attacks.

This incident underscores the risks associated with password reuse across multiple platforms and highlights the importance of unique passwords and the use of multi-factor authentication to enhance security.

What are some high-profile credential stuffing attacks?

Several high-profile credential stuffing attacks have highlighted the vulnerability of user accounts across various services. Here are some notable examples:

1. Yahoo (2012-2016):
   • Over several incidents from 2012 to 2016, Yahoo experienced massive data breaches involving the theft of user credentials. Although initially due to direct hacks, the stolen credentials facilitated subsequent credential stuffing attacks across multiple platforms, affecting millions of users.
2. LinkedIn (2016):
   • In 2016, LinkedIn acknowledged that approximately 117 million accounts were compromised due to a breach that actually occurred in 2012. The credentials obtained were used in credential stuffing attacks on other sites, capitalizing on the users’ tendency to reuse passwords.
3. Dunkin’ Donuts (2018-2019):
   • Dunkin’ Donuts reported several credential stuffing attacks against their DD Perks rewards program accounts in 2018 and 2019. Attackers used previously compromised credentials to access customer accounts to steal rewards points.
4. Reddit (2019):
   • Reddit suffered a credential stuffing attack in February 2019, which led to the breach of several accounts. The attackers used lists of usernames and passwords from other breaches and were successful in logging into some Reddit accounts.
5. DailyMotion (2019):
   • In January 2019, the video-sharing platform DailyMotion reported a credential stuffing attack. The attackers attempted to use stolen credentials to access accounts, prompting DailyMotion to urge all users to reset their passwords as a precaution.

These incidents emphasize the need for robust security practices such as using unique passwords for each account, implementing multi-factor authentication, and educating users about the importance of security hygiene. Credential stuffing attacks exploit the widespread issue of password reuse, and they continue to be a significant threat to online security.