MFA Bypass: 5 Ways Attackers Defeat 2FA (and How to Stop Them)

For years, Multi-Factor Authentication (MFA) was considered the "silver bullet" of cybersecurity. However, as organizations have adopted MFA, attackers have evolved. Today, **MFA bypass attacks** are a common feature of sophisticated phishing campaigns.

1. Adversary-in-the-Middle (AiTM) Phishing

This is currently the most dangerous form of MFA bypass. Unlike traditional phishing that steals just a password, AiTM attacks use a proxy server to sit between the user and the real login page (e.g., Microsoft 365).

2. MFA Fatigue (Push Bombing)

In this attack, the hacker already has the user's password. They trigger dozens of MFA push notifications to the user's phone in the middle of the night or during a busy workday.

The goal is to frustrate or confuse the user into hitting "Approve" just to make the notifications stop. This simple behavioral hack has been used in high-profile breaches at companies like Uber and Cisco.

3. Session Cookie Theft (Infostealers)

Attackers use malware (Infostealers) to scrape the "Remember Me" tokens and session cookies stored in a user's browser. Since these cookies prove the user has already passed MFA, the attacker can simply import them into their own browser and gain instant access.

4. SIM Swapping

By social engineering a telecom provider, an attacker can transfer a victim's phone number to a SIM card they control. This allows them to receive SMS-based MFA codes directly.

5. Vishing (Voice Phishing)

An attacker calls the employee, impersonating the IT department. They claim they are "testing the system" and ask the user to read back the MFA code that was just sent to their device. This low-tech method remains surprisingly effective.

Ready to see how your team handles a real-world MFA bypass simulation? Schedule an AI Phishing Demo today.