Microsoft 365 Safe Attachments vs Advanced Threat Protection — Which Do You Need?

Email remains one of the most commonly exploited entry points for cyberattacks. Microsoft 365 provides built-in tools like Safe Attachments and Safe Links to help mitigate risks, but many organizations are unsure whether these features alone are enough.

This article breaks down what Microsoft 365’s native protections actually cover, when Advanced Threat Protection (ATP) is necessary, and why DMARC plays a critical role in securing your email infrastructure.

Why Email Security Is More Critical Than Ever

Over 90% of cyberattacks begin with a phishing email. According to recent studies:

• 1 in 5 organizations experienced a security breach due to a malicious email
• Business Email Compromise (BEC) caused over $50 billion in losses globally
• AI generated phishing is now indistinguishable from real communication

With more businesses migrating to cloud based productivity suites like Microsoft 365, email threats are evolving to target not just users but also trust systems like your domain name.

What Are Safe Attachments in Microsoft 365?

Safe Attachments is a security feature within Microsoft Defender for Microsoft 365 that scans incoming email attachments for malicious content before delivering them to users. It uses a sandbox environment to analyze attachments in real time.

One of the most effective options within Safe Attachments is Dynamic Delivery. It delivers the message body immediately while scanning the attachment in the background. If the file is clean, it is reattached and delivered; if found malicious, it is dropped entirely. This protects users without delaying communication.

What About Advanced Threat Protection (ATP)?

Advanced Threat Protection refers to a broader set of tools included in highertier Microsoft 365 plans or as addons. It provides additional capabilities such as:

• Realtime threat intelligence
• Automated investigation and response
• Attack simulation training
• Enhanced phishing detection and remediation

ATP extends protection beyond email, securing content in Teams, SharePoint, and OneDrive.

Where Safe Attachments Stop Short

While Safe Attachments effectively handles file based threats, it does not address all email risks. These include:

• Domain spoofing and impersonation
• Authentication failures undetected by content scans
• Malicious links activated after delivery
• Insider threats or compromised user accounts

Organizations relying only on Safe Attachments may miss advanced or socially engineered attacks.

DMARC: The Missing Layer in Microsoft 365

Microsoft 365 supports SPF and DKIM, but full DMARC implementation is not enforced by default. DMARC (Domain based Message Authentication, Reporting, and Conformance) strengthens email security by specifying how mail servers should handle messages that fail authentication checks.

With a properly implemented DMARC policy:

• Your domain is protected from unauthorized use
• You receive reports showing who is sending on your behalf
• Phishing attempts using your domain are reduced
• Customer trust is enhanced

Microsoft 365 does not provide active DMARC enforcement or reporting without additional tools or configuration. A dedicated DMARC solution is essential for full protection.

Safe Attachments vs ATP vs DMARC (Comparison Table)

Feature	Safe Attachments	Advanced Threat Protection (ATP)	DMARC Enforcement
Scans attachments	Yes	Yes	No
Scans URLs in emails	No	Yes (Safe Links)	No
Protects SharePoint/Teams	No	Yes	No
Blocks spoofed senders	No	No	Yes
Provides domainlevel auth	No	No	Yes
Reporting & analytics	Basic	Advanced	Full domainlevel

So, Which Do You Need — Safe Attachments or ATP?

It’s not about choosing one over the other. Each serves a different purpose in your security stack.

Use Safe Attachments if:  You need basic malware protection  You use Microsoft 365 Business Premium  You want seamless protection with minimal setup

Consider Advanced Threat Protection if:  You require broader threat visibility  You collaborate via Teams, SharePoint, or OneDrive  You need automation and advanced analytics

Integrate DMARC if:  You want to prevent spoofing and impersonation  You need visibility into email sources  You aim for complete domain level email protection

Real World Scenarios: What Happens Without DMARC or ATP

Scenario 1: Safe Attachments Only
An executive receives a clean looking email asking for payment. The attachment is safe, but the sender is spoofing your domain. The payment goes through—no alerts are triggered.

Scenario 2: ATP, No DMARC
ATP flags links and suspicious behavior, but the attacker uses a trusted looking sender address (like ceo@yourcompany.com). Users still fall for the scam because the sender passed SPF.

Scenario 3: DMARC + ATP + Safe Attachments
The sender’s domain is unauthenticated, the links are suspicious, and the email is flagged. The message is rejected or quarantined, and your IT team receives a DMARC report with full insight.

The Bottom Line

Safe Attachments offers strong protection against malicious files but doesn’t address all attack vectors. Advanced Threat Protection provides broader coverage across Microsoft 365 apps. DMARC adds enforcement and visibility at the domain level, protecting against impersonation.

A layered approach combining these tools delivers the most effective protection.

Need Help Securing Your Microsoft 365 Environment?

We help businesses implement DMARC, configure Microsoft 365 security features, and close gaps that attackers exploit.

Start with a free domain risk assessment and see where your email protection stands.

Want end-to-end protection against spoofing, phishing, and brand impersonation? Explore our Email Security solutions to see how DMARC, SPF, and DKIM work together to secure your domain and restore trust in your communications.

Securing email is just the start. Discover our full range of Cybersecurity solutions to protect your endpoints, identities, and networks with a comprehensive Zero Trust approach.