How a Microsoft 365 Phishing Attack Unfolds – and How to Stop It

Know what’s happening before it becomes a problem. When a threat actor gains access to an Microsoft 365 account via a phishing attack, it typically follows a structured process.

Step-by-Step Breakdown of the Attack:

1. Phishing Email Sent

The attacker sends a phishing email to the victim.
This email may appear to come from Microsoft, a trusted colleague, or IT support.
It often includes a sense of urgency (“Your account will be locked!”) and a malicious link or attachment.

2. Victim Clicks the Link

The link leads to a spoofed Microsoft 365 login page. It looks nearly identical to the legitimate login page. The victim is prompted to enter their email and password.

3. Credentials Are Captured

The fake login page sends the entered credentials directly to the attacker.
The victim may be redirected to the real Microsoft 365 login afterward, making the attack less suspicious.

4. Account Access Gained

The attacker logs in to the real Microsoft 365 portal using the stolen credentials. If Multi-Factor Authentication (MFA) is not enabled, access is immediate. If MFA is enabled, the attacker might: Use MFA fatigue attacks (keep sending prompts to trick approval), Use SIM-swapping, or Try to phish the MFA code too (e.g., using real-time phishing tools).

5. Post-Exploitation Activities

Once inside the account, the attacker may: Search emails for sensitive info (passwords, invoices, contacts). Impersonate the user to launch further phishing attacks (Business Email Compromise – BEC). Set forwarding rules to monitor future emails silently. Exfiltrate files from OneDrive or SharePoint. Modify MFA settings to maintain persistence.

Mitigation and Prevention Tips

  • Enable MFA for all users.
  • Train staff to spot phishing attempts.
  • Use email security tools (e.g. Microsoft Defender, Proofpoint).
  • Monitor for suspicious logins (e.g. foreign IPs).
  • Set conditional access policies (e.g. block logins from risky locations).
  • Conduct regular phishing simulations.

Your first step – Contact ANother IT and we can help identify your weakness’s tenant wide and help you not only correct them but employ our proactive alert system to pick up on the activity when it occurs and then carry out automated prevention measures 24hours a day 7 days a week to ensure the threat is dealt with effectively and as quickly as possible to ensure your data, finances and reputation remains in tact.

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