eCommerce Fraud Knowledge Guide

Account Takeover Fraud Complete Guide for Merchants

Mark Watson | June 24, 2025

This featured video was created using artificial intelligence. The article, however, was written and edited by actual payment experts.

Everything You Need to Know About Account Takeover Fraud: How it Works & How to Protect Your Business

As a business owner, you probably maintain hundreds of accounts in your personal life, and have dozens more dedicated to your business.

The frightening reality, though, is that every one of these accounts represents a weakness that fraudsters can exploit.

By stealing your login credentials and breaking into your accounts, scammers can conduct unauthorized transactions in your name. They can even use the information they find in your account to compromise other profiles and users — all without your awareness or permission.

Scared? Don’t be. We’ll give you the rundown on what account takeovers are, how they work, and what you can do to protect yourself against this type of fraud.

Account Takeover Fraud

[noun]/uh • kount • teyk • oh • ver • frawd/

Account takeover fraud, or ATO fraud, is a form of identity theft by which a third party gains access to unique details of a trusted user’s online accounts. Fraudsters can pose as the real customer to change account details, make purchases, withdraw funds, and even leverage the stolen information to access other accounts.

Scammers often target accounts holding financial data or personally identifiable info (name, address, Social Security number, etc.). However, they may also target a variety of different profiles, including:

  • Social media accounts can be used to mislead and manipulate your followers.
  • Email accounts to mine personal info or reset passwords for other accounts.
  • Bank accounts to steal money, infiltrate financial services, or secure loans.
  • Amazon or other shopping accounts to make purchases and steal card info.

The insidious nature of account takeover fraud lies in the scammer’s desire to operate undetected, exploiting stolen credentials for as long as they can.

How Does Account Takeover Work?

Account takeovers happen when attackers gain access to username and password combinations through illicit means, and then use these stolen credentials to gain unauthorized access to online accounts that do not belong to them.

But, how exactly does an account takeover attack happen? It’s actually pretty simple:

Steal Login Credentials

Step #1 | Steal Login Credentials

An attacker obtains valid username and password combinations through methods including phishing, brute-force attacks, or purchasing the information from data brokers.

Access the Account

Step #2 | Access the Account

The attacker logs into the targeted account using the stolen credentials without the legitimate user’s knowledge or consent.

Exploit the Account

Step #3 | Exploit the Account

The attacker engages in unauthorized activity, changes the login credentials to lock the legitimate user out, and may even use information gained from the account to conduct further attacks.

Chapter 1

Common Account Takeover Tactics

Fraudsters can steal login credentials and access online accounts using a variety of methods, including phishing, SIM swapping, malware, brute force attacks, and other tactics. Once in possession of a single working username and password combination, scammers can potentially compromise many other accounts due to password reuse.

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Chapter 2

Account Takeover Fraud Statistics

Cardholders, merchants, and financial institutions are all routine targets for account takeover attempts. And, a single account takeover attack can be devastating in all three demographics.

Merchants, for example, may face chargebacks, reputational damage, and higher operational costs. Financial institutions can incur substantial financial liability, loss of customer confidence, and greater security costs.

Cardholders, despite often benefiting from $0 fraud liability guarantees, may still lose control of their personally identifying information (PII). They could also be forced to spend significant time and effort to resolve fraud-related issues that arise.

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Chapter 3

Account Takeover Case Studies

Account takeovers routinely happen to millions of cardholders and merchants every year in the US. Single attacks, carried out on large and vulnerable accounts, can result in thousands — or even millions — of dollars in losses per incident.

Here, we detail some real-world examples of account takeover attacks, highlighting the fraudsters behind them and illustrating the tangible financial consequences caused by these attacks.

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Chapter 4

How to Identify Account Takeover

Account takeover attacks are difficult to spot… but they don’t occur without warning. Pay careful attention, and you may be able to notice some telltale signals.

While red flags can differ depending on how fraudsters choose to break in, you can reliably use these warning signs to sniff out when an unauthorized login attempt may be imminent.

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Chapter 5

How to Prevent Account Takeover

At the end of the day, detection alone is not enough. Instead, it’s prevention that counts.

Stopping even a single account takeover from proceeding can save you hundreds of thousands of dollars. That’s not to mention the headaches of resolving the fraud-related fallout that would otherwise occur.

From strong passwords, multi-factor authentication, and multilayered prevention strategies to where to seek professional help, cardholders and merchants can take these actionable steps to keep their accounts secure and out of reach of scammers.

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FAQs

What is an example of account takeover?

One example of an account takeover may involve a brute force login attempt that targets a cardholder’s bank account. Here, a scammer uses credential stuffing tactics to cycle through thousands of stolen username and password pairs at once. If a combination works, the fraudster can gain unauthorized access to the victim’s account.

What is the difference between identity theft and account takeover?

Identity theft can be thought of as the precursor to, or enabler of, account takeover fraud. Put another way, all account takeover attempts involve identity theft, but not all identity theft necessarily results in account takeovers.

Some identity thieves may use stolen personally identifying information (PII) to create new accounts themselves, or simply sell the illicitly-obtained data on the dark web.

What is the typical method of account takeover?

Account takeovers most often happen when attackers gain access to username and password combinations through phishing tactics or data breaches. Once in possession of these login credentials, fraudsters may use common tactics like credential stuffing to attempt logins.

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