Defender for Office 365Anti-Phishing & Impersonation Protection

Anti-Phishing & Impersonation Protection

20 mins

Understanding the Concept

Defender for Office 365 anti-phishing policies use machine learning and heuristic analysis to detect phishing attempts. Impersonation protection specifically guards against attacks that spoof trusted users (user impersonation) or trusted domains (domain impersonation).

Mailbox intelligence enhances impersonation detection by learning each user's email patterns and flagging deviations. First contact safety tips warn users when they receive email from someone for the first time.

Anti-spoofing protection uses SPF, DKIM, and DMARC validation along with implicit authentication to determine email legitimacy. The spoof intelligence insight shows senders who are spoofing your domain.

Key Points

  • ML-based phishing detection with impersonation protection
  • User impersonation: protects specific high-value users (CEO, CFO)
  • Domain impersonation: protects against lookalike domains
  • Mailbox intelligence learns user email patterns for anomaly detection
  • Anti-spoofing uses SPF, DKIM, DMARC validation
  • Spoof intelligence provides visibility into spoofing attempts

Why This Matters in Real Organizations

Business Email Compromise (BEC) attacks cost organizations billions annually. Impersonation attacks targeting executives and finance teams bypass traditional email filtering because they use legitimate-looking sender addresses.

Common Mistakes to Avoid

Not adding VIP users to impersonation protection lists
Ignoring the spoof intelligence insight for tuning
Not enabling first contact safety tips
Relying solely on SPF/DKIM without DMARC enforcement

Interview Tips

  • Explain the difference between spoofing and impersonation
  • Discuss BEC attack patterns and how anti-phishing policies prevent them

Exam Tips (SC-200)

  • Know the anti-phishing policy components
  • Understand user vs domain impersonation protection
  • Know how mailbox intelligence enhances detection

Course Complete!

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