Understanding and Preventing Account Takeover

PUBLISHED ON January 25, 2022
LAST UPDATED April 20, 2022

In the previous installment of our blog series on the modern threat landscape, we looked at how attackers can use credential stuffing attacks to break into valid user accounts. Today, we will continue to follow that theme by diving into the world of account takeovers (ATOs) to see how attackers use compromised accounts to commit fraud. 

Like other threats covered in this series, account takeovers are problematic for traditional OWASP-style WAF rules. While these rules look for overt malicious actions such as injections or XSS attempts, an account takeover involves an attacker who has already gained credentialed access to a user’s account. At this point, there is typically no need for a traditional exploit as the attacker will perform various types of fraud with the compromised user’s account. 

Security teams will need new tools and perspectives that are designed for this growing class of threat. So let’s dive in to better understand what ATOs are and what organizations can do to protect their applications and users.

Learn more about how cyberattacks are evolving in our new guide, What Lies Beneath: What You Need to Know About the Modern Threat Landscape.

Causes of Account Takeovers

Account takeovers represent one of the latest stages in the lifecycle of an attack in which an attacker attempts to turn previous hacking efforts into some form of profit. Security teams are naturally motivated to disrupt these attacks as early as possible before the ATO can ever take place. However, there are many ways attackers can gain initial control over a user’s account; some will directly involve the application, and some will not. As a result, it is often impossible for an organization to fully prevent ATO attacks upstream. Some of the most common ATO enablers include:

  • Credential Stuffing – Credential stuffing attacks attempt to break into an account by reusing account credentials exposed in a previous breach. This technique takes advantage of the fact that users will often reuse the same password on multiple online accounts. These efforts naturally involve trying large numbers of credentials and thus are typically the work of large-scale botnets. It is important to note that credential stuffing does involve attackers directly testing the application, meaning that using anti-bot protections can significantly reduce this precursor of an account takeover.
  • Phishing and Social Engineering – Phishing is one of the most tried and true methods of gaining a victim’s credentials. Attackers will often spoof emails that appear to come from a particular application encouraging the user to login, only to lead the user to a fake version of a site where the user’s credentials can be harvested. Phishing attacks can also lead to the installation of malware or keyloggers that can capture credentials to any number of applications over time. It is very difficult to fully prevent these techniques since they involve actions that users take when not on the application itself. However, support for multi-factor authentication can help to mitigate the impact of stolen credentials.
  • Malware, Trojans, and Man-in-the-Browser – Instead of using malware to harvest credentials, attackers can also use malware to directly manipulate an application while the user is logged in. These techniques were pioneered by banking trojans but have since spread to other forms of malware. In this case, the malware can act as somewhat of a parasite, riding along with the valid user through the authentication process, then automating malicious actions in the background once the user is connected. These techniques are particularly insidious as they will use the valid end-user to complete any secondary factors of authentication.

Impacts of Account Takeovers

Account takeovers have long been associated with financial fraud, and while this remains a primary motivation today, it is important to remember that many types of accounts can be abused by an ATO. This can include:

  • Direct Financial Fraud – A compromised financial account can let attackers initiate fraudulent transfers to directly steal funds. Attackers can also open additional accounts or credit cards that can then be abused. 
  • Indirect Financial Fraud – Attackers will also abuse accounts in more indirect ways to make money. For example, they can buy gift cards or steal a user’s points, which can then be resold. This may seem like small impacts, but gift cards are heavily used by criminal groups as a way to launder money.
  • Spam and Phishing – Many applications are inherently social and foster user interaction. By compromising an account, attackers can use this trusted position to lure other users into making dangerous clicks. 
  • Fake Reviews, Astroturfing  – Applications can also be abused in order to manipulate public opinions. For example, an attacker can use compromised accounts to create fake reviews for fraudulent products. Similarly, fake user clicks and comments can be used to manipulate social media and trending content.

How ThreatX Protects  Against Account Takeovers

ThreatX arms application security teams and anti-fraud teams with a variety of ways to combat and analyze ATOs. This can include preventing account take-overs, detecting active abuse of an account, as well as providing ongoing monitoring of suspicious behavior to enable ongoing fraud analysis efforts. While the details are naturally always changing as we adapt to stay ahead of attackers, we have highlighted some of the most important traits below:

  • Active Interrogation of Visitors –  ThreatX actively challenges visitors in ways that are completely transparent to valid users while reliably revealing malicious automation. These challenges can detect and block attacker attempts to use bots both before and after an account is compromised. This can prevent the overall number of ATOs while also disrupting ATO abuse that is already in progress.
  • Fingerprinting and Entity Tracking – ThreatX leverages some of the most advanced fingerprinting techniques in the industry to track attackers even as they change IP addresses, user agents, or other identifying characteristics. This ensures blocking decisions can see all preceding malicious or suspicious events in context in order to make ATO blocking decisions based on a complete view of risk.
  • Automated Deception Techniques – The platform can introduce deceptive techniques such as fake fields that are readable to bots but invisible to users. Any interaction with these fields or functions can reveal that the visitor is a bot and not a human. Additionally, the platform can tarpit or further deceive attackers to monitor and observe ongoing malicious behavior.
  • Application Profiling and Behavioral Analysis – In addition to profiling attacker behavior, ThreatX also baselines and monitors the normal behavior of applications. Since many ATOs rely on malicious automation, ThreatX can detect anomalous and suspicious application behaviors to reveal a previously undetected account takeover.

These techniques represent just a few of the techniques and countermeasures that ThreatX uses every day against account takeovers. Many of these same techniques are used to combat other types of threats, and this is by design. Instead of designing specialized countermeasures aimed at specific threats, our philosophy at ThreatX is to build blended protection strategies capable of dealing with any threat. All available perspectives and techniques are applied and correlated to every event. 

Learn more about how cyberattacks are evolving and what’s needed to thwart them in our new guide, What Lies Beneath: What You Need to Know About the Modern Threat Landscape.

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About the Author

Bret Settle

Bret has served in multiple executive roles for Corporate Express/Staples and BMC Software and has extensive knowledge of the software development and security products industries. Bret has been responsible for enterprise security in multiple roles and has been an innovator throughout his career and has a proven track record of building and developing high performing organizations and dynamic cyber security teams.