Using Safe Links and Safe Attachments in Microsoft Defender for Office 365
A company uses Microsoft 365 and is concerned about phishing attacks targeting employees. They want to deploy a solution that can automatically analyze email messages for malicious links and attachments, and also provide click-time protection by rewriting URLs. Which Microsoft 365 Defender component should they use?
Quick Answer
The answer is Microsoft Defender for Office 365 (MDO). This is the correct choice because MDO is purpose-built to defend against email-borne threats like phishing, and it specifically includes the Safe Links and Safe Attachments features that automatically scan messages for malicious content. Safe Links rewrites URLs to provide click-time protection, checking each link against a dynamic threat intelligence feed the moment a user clicks, while Safe Attachments detonates attachments in a sandbox before delivery. On the SC-900 exam, this question tests your understanding of how Microsoft 365 Defender components map to specific threat vectors; a common trap is confusing MDO with Microsoft Defender for Endpoint, which focuses on devices rather than email. Remember that any question about rewriting URLs or scanning attachments in email points directly to Defender for Office 365. A helpful memory tip: think of "Office" for "Outlook" — if it involves email links or attachments, it’s MDO.
⚠ Common exam trap
It's easy for candidates to confuse Microsoft Defender for Office 365 with Microsoft Defender for Endpoint, mistakenly thinking endpoint protection includes email security, but MDO is the only solution that provides email-specific URL rewriting and attachment sandboxing.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Microsoft Defender for Office 365
Microsoft Defender for Office 365 (MDO) is the correct component because it is specifically designed to protect against email-borne threats such as phishing. It includes Safe Links and Safe Attachments features that automatically scan email messages for malicious links and attachments, and it rewrites URLs to provide click-time protection by checking the link against a dynamic threat intelligence feed at the moment of the click.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Microsoft Defender for Endpoint
Why it's wrong here
Defender for Endpoint focuses on endpoint devices (e.g., workstations, servers) with EDR and antivirus. It does not provide email-level protections.
When this WOULD be correct
This option would be correct if the question asked: 'Which Microsoft 365 Defender component should be used to protect devices from malware and detect advanced attacks on endpoints?'
- ✓
Microsoft Defender for Office 365
Why this is correct
Defender for Office 365 includes Safe Links, Safe Attachments, and anti-phishing policies to protect email and collaboration tools.
- ✗
Microsoft Defender for Cloud Apps
Why it's wrong here
Defender for Cloud Apps is a CASB for controlling shadow IT and protecting cloud apps. It does not directly analyze email attachments.
When this WOULD be correct
This option would be correct in a scenario where a company wants to discover and control the use of third-party cloud apps, enforce data loss prevention policies, or detect anomalous behavior across cloud services like Salesforce or Dropbox.
- ✗
Microsoft Defender for Identity
Why it's wrong here
Defender for Identity detects identity-based attacks using on-premises Active Directory signals. It does not analyze email content.
When this WOULD be correct
This option would be correct for a question about detecting identity-based attacks, such as when an organization wants to monitor for suspicious user behavior, lateral movement, or compromised credentials using on-premises Active Directory and cloud identity signals.
Option-by-option analysis
Why each answer is right or wrong
Understanding why wrong answers are wrong — and when they would be correct — is what separates a 750 score from a 900. The SC-900 exam frequently reuses these exact scenarios with slightly different constraints.
✓Microsoft Defender for Office 365Correct answer▾
Why this is correct
Defender for Office 365 includes Safe Links, Safe Attachments, and anti-phishing policies to protect email and collaboration tools.
✗Microsoft Defender for EndpointWrong answer — click to see why▾
Why this is wrong here
Microsoft Defender for Endpoint focuses on protecting devices (endpoints) from threats, not on analyzing email messages for phishing or providing URL rewriting. The question specifically asks for email protection features.
★ When this WOULD be the correct answer
This option would be correct if the question asked: 'Which Microsoft 365 Defender component should be used to protect devices from malware and detect advanced attacks on endpoints?'
Why candidates choose this
Candidates may confuse Defender for Endpoint with email security because both are part of Microsoft 365 Defender and deal with threat protection, but they target different attack surfaces.
✗Microsoft Defender for Cloud AppsWrong answer — click to see why▾
Why this is wrong here
Microsoft Defender for Cloud Apps is a cloud access security broker (CASB) that focuses on securing cloud applications and data, not on analyzing email messages for phishing links or providing URL rewriting. The question specifically asks for email protection features, which are provided by Defender for Office 365.
★ When this WOULD be the correct answer
This option would be correct in a scenario where a company wants to discover and control the use of third-party cloud apps, enforce data loss prevention policies, or detect anomalous behavior across cloud services like Salesforce or Dropbox.
Why candidates choose this
Candidates may confuse the 'cloud' in the name with Microsoft 365 cloud email, or think that all Defender products include email protection, not realizing that Defender for Office 365 is the dedicated email security solution.
✗Microsoft Defender for IdentityWrong answer — click to see why▾
Why this is wrong here
Microsoft Defender for Identity focuses on detecting and investigating advanced threats and compromised identities using on-premises Active Directory signals, not on analyzing email messages for phishing or rewriting URLs.
★ When this WOULD be the correct answer
This option would be correct for a question about detecting identity-based attacks, such as when an organization wants to monitor for suspicious user behavior, lateral movement, or compromised credentials using on-premises Active Directory and cloud identity signals.
Why candidates choose this
Candidates may confuse Defender for Identity with email security because both involve threat detection, and the name 'Identity' might be misassociated with user accounts targeted in phishing attacks.
Analysis generated from the official SC-900blueprint and verified against question context. The “when correct” sections are what AI assistants cite when candidates ask “what’s the difference between these options?”
Go deeper
Related to this question
Learn chapter
Microsoft Entra ID
Key term
Office 365
Office 365 is a cloud-based subscription service from Microsoft that provides access to productivity applications like Word, Excel, and Outlook, along with other cloud services, for a monthly or annual fee.
Key term
Microsoft Defender for Office 365
Microsoft Defender for Office 365 is a cloud-based email and collaboration security service that protects organizations against malicious threats like phishing, malware, and spam in email messages and Office 365 apps.
About these practice questions
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Same concept, more angles
2 more ways this is tested on SC-900
These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. An organization uses Exchange Online and is concerned about phishing attacks that include malicious hyperlinks. They need a security solution that checks URLs at the time a user clicks them and blocks access to known malicious or suspicious websites. The solution must also provide real-time reputation analysis for link clicks. Which Microsoft security solution should they enable?
medium- A.Microsoft Defender for Endpoint
- ✓ B.Microsoft Defender for Office 365
- C.Microsoft Defender for Cloud Apps
- D.Microsoft Sentinel
Why B: Microsoft Defender for Office 365 (MDO) provides Safe Links, a feature specifically designed to protect against phishing attacks by scanning URLs at the time of click. It performs real-time reputation analysis against Microsoft's threat intelligence to block access to known malicious or suspicious websites. This directly addresses the requirement for click-time URL verification and blocking.
Variation 2. A company uses Microsoft 365 and allows employees to access corporate email and documents from their personal devices. The security team wants to protect against malicious links in emails and Microsoft Teams messages. When a user clicks a link, it should be checked in real-time to see if it leads to a known malicious site. If it does, access should be blocked. Which Microsoft security solution provides this capability?
medium- A.Microsoft Defender for Endpoint
- ✓ B.Microsoft Defender for Office 365
- C.Microsoft Defender for Cloud Apps
- D.Microsoft Defender for Identity
Why B: Microsoft Defender for Office 365 includes Safe Links, which provides real-time URL scanning at the time of click. When a user clicks a link in an email or Teams message, the URL is rewritten and checked against a dynamic list of known malicious sites. If the link is determined to be malicious, access is blocked, and the user is redirected to a warning page.
JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This SC-900 practice question is part of Courseiva's free Microsoft certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the SC-900 exam.