SC-200 Respond to security incidents Practice Question
Your organization uses Microsoft Defender for Office 365. You detect a phishing email that was delivered to a user's inbox. You want to remove the email from all recipients. What should you do?
⚠ Common exam trap
It's easy for candidates to confuse proactive blocking (e.g., blocking the sender or creating a rule) with reactive remediation, failing to recognize that Threat Explorer is the only option that can remove already-delivered emails from user mailboxes.
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
✓
Use Threat Explorer to find the email and take action to delete it.
Threat Explorer in Microsoft Defender for Office 365 allows security analysts to search for specific emails based on attributes like sender, subject, or recipient, and then take bulk remediation actions such as soft-delete (move to Deleted Items) or hard-delete (purge from mailbox). This is the correct tool to remove a phishing email that has already been delivered to users' inboxes, as it provides granular search and remediation capabilities for existing messages.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Submit the email to Microsoft for analysis.
Why it's wrong here
Submitting the email to Microsoft for analysis (e.g., via the Submission portal in Defender for Office 365) sends the item to Microsoft for threat research and potentially improves filter detections, but it does not remove the email from user mailboxes. The submission process is a feedback loop for malware/phishing verdicts, not a remediation action, so it leaves the original email in place and fails to address the immediate incident.
- ✗
Create a mail flow rule to delete similar emails in the future.
Why it's wrong here
Creating a mail flow rule (transport rule) in Exchange Online can block or delete future messages that match sender/recipient/subject criteria, but it only applies to new messages as they flow through the pipeline. It has no effect on emails already delivered to mailboxes, so it cannot remediate the current message that is already sitting in users' inboxes.
- ✗
Block the sender using the Tenant Allow/Block List.
Why it's wrong here
Adding the sender to the Tenant Allow/Block List in the Defender portal (or the corresponding block list) stops any future emails from that sender from being delivered, and will mark those future messages as blocked. However, the block list acts on inbound delivery decisions only; it does not search or delete messages already delivered to mailboxes, so existing emails remain accessible to users.
- ✓
Use Threat Explorer to find the email and take action to delete it.
Why this is correct
Threat Explorer (part of Microsoft Defender for Office 365) provides a deep, filterable view of email activity, including sender, recipient, subject, and threat signals. You can locate the specific email(s) that match the attack, select them, and use the 'Take action' drop-down to choose 'Delete' (or 'Soft delete/Delete'), which performs a bulk removal of the message from all affected mailboxes and can optionally trigger a remediation action. This is the appropriate tool because it combines search, investigation, and remediation for already-delivered threats.
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This SC-200 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-200 exam.