Abusing Microsoft 365 OAuth Authorization Flow for Phishing Attack

O365DevicePhish

Microsoft365_devicePhish Abusing Microsoft 365 OAuth Authorization Flow for Phishing Attack

This is a simple proof-of-concept script that allows an attacker to conduct a phishing attack against Microsoft 365 OAuth Authorization Flow. Using this, one can connect to Microsoft's OAuth API endpoints to create user_code and device_code and obtain victim user's access_token upon successfult phishing attack. Then, the token can be used to access various Office365 products via Microsoft Graph API on behalf of the victim user. In addition, this script was created to help a specific situation where a target organization was utilizaing an Email OTP (One-time Passcode) for their MFA option; thus, with a successful phishing attack, one could read a generated Email OTP code from victim user's email inbox to bypass MFA.

Usage

$ python3 devicePhish.py 
[INFO] Usage: python3 devicePhish.py 
   
    
[INFO] Example: python3 devicePhish.py fake-2ce0-4958-a61a-a5055ef62bf8

   

Example

1. Generating user_code and device_code from an Azure App:

2. Upon successfull phishing attack, obtaining access_token & refresh_token for a victim user:

3. After an Email OTP is triggered, reading the OTP code from the victim's email inbox:

4. After reading the Email OTP code, it deletes the OTP email:

Credits & References

• Introducing a new phishing technique for compromising Office 365 accounts