8 Powerful Account Takeover (ATO) Methods and How to Exploit Them

Account Takeover (ATO) is a critical security vulnerability that allows attackers to hijack user accounts through various techniques. In this article, we’ll cover 8 powerful ATO methods, provide practical exploitation steps, and discuss how to mitigate these attacks effectively.

Concept: Some web applications mishandle Unicode characters, allowing attackers to create accounts that visually resemble legitimate ones.

Exploitation Steps:

Identify a victim’s email, e.g., victim@gmail.com.Register a new account with a visually similar Unicode character, e.g., vićtim@gmail.com (note the ć).If the platform does not normalize Unicode properly, attackers can reset the password on the real victim’s account and gain access.

🔗 List of Unicode characters: Unicode Character Table

Mitigation:

✅ Normalize and validate email addresses before storing them.

✅ Use case-insensitive and Unicode-aware email comparisons.

Concept: Poor authorization checks allow attackers to hijack accounts during email change requests.

Exploitation Steps:

Change Account A’s email to email_B@example.com.Check the confirmation email sent to email_B@example.com.Open the confirmation link using Account C, which results in Account C being taken over.

Mitigation:

✅ Require the current password before changing email.

✅ Use strict email verification with unique per-user tokens.

✅ Implement session invalidation after email change.

ATO — @verylazytech