What are Account Takeover Attacks?

Account takeover attacks can compromise sensitive information. Learn effective strategies to prevent these attacks and secure your accounts.
Author: SentinelOne Updated: July 31, 2025

Account takeover attacks occur when an unauthorized user gains access to an account. This guide explores the tactics used in these attacks and effective prevention strategies.

Learn about the importance of strong passwords, multi-factor authentication, and user education. Understanding account takeover attacks is crucial for protecting sensitive information and maintaining user trust.

Understanding the Mechanics of Account Takeover Attacks

To effectively combat ATO attacks, it’s crucial to understanding cybercriminals’ methods. Here are some common techniques used in account takeovers:

  • Credential Stuffing – Attackers use automated bots to test stolen username and password combinations across multiple sites, capitalizing on the tendency of users to reuse login credentials.
  • Brute Force Attacks – Cybercriminals employ bots to systematically try various password combinations until they gain access to an account.
  • Phishing – Scammers trick users into revealing their login information through deceptive emails, text messages, or phone calls.
  • Man-in-the-Middle (MitM) Attacks – Hackers intercept and manipulate internet traffic, potentially gaining access to unencrypted login credentials.

Preventing Account Takeover | Best Practices for Organizations

Organizations can take several proactive measures to reduce the risk of ATO attacks and protect their customers’ information:

  • Implement Multi-Factor Authentication (MFA) – Require users to verify their identity using an additional factor, such as a fingerprint, facial recognition, or a one-time code sent to their mobile device.
  • Monitor User Behavior – Continuously track account activity and flag any unusual patterns, such as multiple failed login attempts, logins from new devices, or logins from suspicious locations.
  • Employ AI-Based Detection – Utilize advanced artificial intelligence technology to identify and block sophisticated ATO attempts, including those using advanced bots that mimic human behavior.
  • Deploy a Web Application Firewall (WAF) – Protect your website and applications by filtering and blocking malicious traffic using a WAF, which can detect and prevent credential stuffing, brute force attacks, and other ATO methods.

In addition to implementing the best practices outlined above, organizations should also explore advanced solutions to bolster their defenses against ATO attacks:

  • Behavioral Analytics – Implement a system that analyzes user behavior in real time, identifying anomalies and potentially malicious activities that may signal an account takeover attempt.
  • Risk-Based Authentication – Adjust authentication requirements based on the perceived risk of a login attempt. For example, prompt for additional verification when a user logs in from an unfamiliar device or location.
  • Regular Security Audits and Penetration Testing – Conduct periodic assessments of your security infrastructure and processes to identify vulnerabilities and areas for improvement.
  • Incident Response Plan – Develop and maintain a comprehensive incident response plan that outlines the steps to take when an account takeover or other security breach is detected.

Educating Users | Key Strategies for Account Takeover Prevention

While organizations play a crucial role in preventing ATO attacks, users must also take responsibility for protecting their personal information. Here are some essential tips for individuals:

  • Create Strong, Unique Passwords – Use a combination of upper and lowercase letters, numbers, and symbols to create strong passwords, and avoid using the same password across multiple accounts.
  • Enable Multi-Factor Authentication – Whenever possible, enable MFA for your accounts to provide an additional layer of security.
  • Beware of Phishing Attempts – Be cautious of unsolicited emails, text messages, or phone calls asking for your login information, and never click on suspicious links or provide your credentials to unknown parties.
  • Update Security Software – Keep your endpoint security software and operating system up-to-date to protect against malware.
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Understanding Account Takeover in the Context of Cloud Security

As businesses increasingly migrate their operations to the cloud, they must contend with the unique security challenges in this environment. Account takeover is particularly concerning, as it represents a direct assault on the heart of cloud security: user accounts.

In an ATO attack, cybercriminals exploit compromised credentials to gain unauthorized access to online accounts. They typically obtain these credentials through data breaches, phishing campaigns, or purchasing them on the dark web. Once they have control of an account, attackers can exfiltrate sensitive data, carry out fraudulent transactions, or perpetrate other forms of cybercrime.

SentinelOne Singularity XDR – A Comprehensive Solution for Account Takeover Protection

SentinelOne Singularity XDR offers a robust, all-encompassing solution that protects organizations from business logic attacks, including account takeover attempts. By extending coverage to all access points – from endpoints and users to cloud workloads and other devices – Singularity XDR delivers unparalleled visibility and security.

Key features of SentinelOne Singularity XDR that help defend against ATO attacks include:

  • Endpoint Protection – Secure endpoints with advanced machine learning algorithms that detect and block malicious activities in real-time, including attempts to compromise user accounts.
  • User Behavior Analytics – Analyze user behavior patterns to identify potential account takeover attempts and take immediate action to prevent unauthorized access.
  • Cloud Workload Security – Protect your cloud infrastructure with automated CWPP enforcement, real-time monitoring, and threat detection, ensuring a secure environment for user accounts and sensitive data.
  • Integration with Existing Security Infrastructure – SentinelOne Singularity XDR seamlessly integrates with your existing security stack, enhancing your organization’s overall defense against ATO and other cyber threats.

Conclusion | Staying One Step Ahead of Account Takeovers

Account takeover attacks are a pervasive and evolving threat, but by understanding the tactics used by cybercriminals and implementing robust security measures, organizations and individuals can significantly reduce their risk of falling victim to these attacks. By understanding the techniques employed by cybercriminals, implementing best practices for security, and adopting advanced solutions like SentinelOne Singularity XDR, organizations can proactively defend against ATO attacks and ensure the ongoing security of their cloud environment.

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Account Takeover Attack FAQs

What is an Account Takeover (ATO) Attack?

An account takeover (ATO) happens when attackers gain unauthorized access to a user’s online account. They use stolen or guessed credentials to log in and perform actions like stealing data, making purchases, or spreading fraud. It’s a common way cybercriminals abuse trusted accounts to bypass security and cause damage.

How does an Account Takeover Attack Work?

Attackers start by stealing or guessing usernames and passwords, often via phishing or credential dumps. Once they have valid credentials, they log into the target account and change passwords or settings to lock the real user out. They may also use the account for fraudulent activities or identity theft before being detected.

What are the most common methods used in ATO Attacks?

Phishing emails trick users into handing over credentials. Credential stuffing uses leaked username-password combos to break into accounts. Keyloggers record passwords typed on infected devices. Social engineering convinces users to reveal login info. Sometimes attackers exploit weak or reused passwords to gain easy access.

Which Types of Accounts are most commonly targeted in ATO Attacks?

Financial accounts like banking and payment services are prime targets. Email and social media accounts get hit to harvest info or spread malware. E-commerce and subscription services are also at risk, as attackers attempt unauthorized purchases or identity theft. Any account with valuable data or access is a possible target.

Can MFA (multi-factor authentication) Prevent ATO Attacks?

MFA is very effective at stopping ATOs by requiring a second verification step like a code or biometric check. Even if credentials are stolen, attackers can’t enter without the additional factor. While not foolproof, enabling MFA drastically cuts the risk and buys time for detection.

What are common signs of an Account Takeover in Progress?

Look for unusual login locations or devices, sudden password changes, or unexpected account lockouts. Alerts of failed login attempts or triggered security notifications can also hint at takeover. Odd activity like strange emails sent from the account or unauthorized transactions should raise alarms quickly.

How can Organizations Detect unusual login patterns?

Use security tools that analyze login geolocation, device fingerprints, and access times to spot anomalies. Set up alerts for impossible travel between logins or multiple failed attempts. Correlate behavior with past usage patterns to identify suspicious access before damage happens.

What are the Best Practices to Prevent Account Takeover Attacks?

Enforce MFA on all accounts and block reused or weak passwords. Regularly update and patch systems to close vulnerabilities. Train employees to spot phishing and social engineering. Monitor login activity closely and respond fast to suspicious events. Limit privileges to reduce the impact of any successful attacks.

What should Organizations do after detecting an Account Takeover?

Immediately isolate the affected account by resetting passwords and revoking sessions. Investigate the breach’s scope and notify the impacted user. Scan for malware or compromised systems. Report to relevant authorities if needed. Review and close gaps that allowed the attack to prevent recurrence.

How often should Organizations audit account access to prevent takeover risk?

Conduct access reviews at least quarterly, or more often if you handle sensitive data or see increased attacks. Audit permission changes, inactive accounts, and MFA enforcement. Continuous monitoring with automated alerts helps catch risky behavior in real-time and supports proactive security management.

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