Investigate and remediate threats with Defender for Office 365
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Microsoft Defender for Office 365 provides comprehensive threat investigation and remediation capabilities for security operations analysts. This solution protects organizations against malicious threats posed by email messages, links, and collaboration tools.
When investigating threats, analysts …Microsoft Defender for Office 365 provides comprehensive threat investigation and remediation capabilities for security operations analysts. This solution protects organizations against malicious threats posed by email messages, links, and collaboration tools.
When investigating threats, analysts use Threat Explorer (also known as Explorer) to analyze threats in real-time. This powerful tool allows you to view malware detected in email, identify phishing attempts, and see the email timeline for suspicious messages. You can filter data by sender, recipient, subject, attachment, and delivery action to narrow down potential threats.
The investigation process typically involves several steps. First, analysts review alerts generated by Defender for Office 365 in the Microsoft 365 Defender portal. These alerts highlight suspicious activities such as malicious attachments, compromised users, or suspicious sending patterns. Next, analysts can use Automated Investigation and Response (AIR) capabilities, which automatically investigate alerts and provide remediation actions.
Remediation actions in Defender for Office 365 include soft delete of email messages, blocking URLs, turning off external mail forwarding, and removing delegates. The Action Center displays all pending and completed remediation actions, allowing analysts to approve, reject, or undo actions as needed.
Threat Trackers provide another valuable investigation tool, offering widgets and views about cybersecurity issues that might affect your organization. Campaign Views help identify coordinated phishing and malware campaigns targeting your organization.
For email-specific threats, analysts can perform message traces to follow the path of messages and determine why specific emails were delivered, quarantined, or blocked. Real-time detections provide visibility into attacks as they happen, enabling faster response times.
Integration with Microsoft Sentinel enhances these capabilities by correlating Defender for Office 365 data with other security signals across the enterprise, providing a unified view of threats and enabling more effective incident response across the entire organization.
Investigate and Remediate Threats with Defender for Office 365
Why This Is Important
Microsoft Defender for Office 365 is a critical component of an organization's security posture, protecting against sophisticated threats like phishing, business email compromise, and malware delivered through email and collaboration tools. As a Security Operations Analyst, understanding how to investigate and remediate these threats is essential for maintaining organizational security and passing the SC-200 exam.
What Is Defender for Office 365?
Defender for Office 365 is a cloud-based email filtering service that protects organizations against unknown malware and viruses by providing robust zero-day protection. It includes features for investigating threats, hunting for malicious activity, and taking remediation actions across email and Microsoft Teams.
Key Investigation Tools
Threat Explorer (Real-time Detections) - Provides near real-time visibility into threats - Allows filtering by sender, recipient, subject, and detection technology - Shows malware, phish, and spam detections - Available in Plan 2 (full Explorer) and Plan 1 (Real-time detections)
Automated Investigation and Response (AIR) - Automatically investigates alerts and suspicious activities - Groups related alerts into incidents - Provides recommended remediation actions - Can be configured for automatic or manual approval of actions
Campaigns View - Identifies coordinated phishing and malware campaigns - Shows the scope and timeline of attacks - Helps understand attack patterns targeting your organization
How Investigation Works
1. Alert Triggered: Security alerts are generated when threats are detected 2. Investigation Initiated: AIR begins analyzing the alert and related entities 3. Evidence Collection: System gathers email metadata, URLs, attachments, and user activities 4. Analysis: Threats are correlated and scored based on severity 5. Recommendations: Remediation actions are suggested based on findings
Remediation Actions Available
- Soft delete emails: Moves messages to Deleted Items folder - Hard delete emails: Permanently removes messages - Block URL: Adds malicious URLs to the block list - Block sender: Prevents future emails from specific senders - Submit for analysis: Sends samples to Microsoft for deeper investigation - Trigger investigation: Manually starts an automated investigation
Threat Hunting with Explorer
Use Threat Explorer to: - Search for specific IOCs (Indicators of Compromise) - Identify all recipients of a malicious email - Track delivery status of suspicious messages - Review URL clicks and Safe Links data - Analyze attachment detonation results from Safe Attachments
Exam Tips: Answering Questions on This Topic
Key Differentiators to Remember:
1. Plan 1 vs Plan 2: Threat Explorer is only available in Plan 2. Plan 1 offers Real-time detections with limited functionality.
2. AIR Approval Settings: Know the difference between automatic remediation and requiring approval. Default behavior varies by action type.
3. Soft Delete vs Hard Delete: Soft delete allows recovery; hard delete does not. Questions often test when each is appropriate.
4. Time Ranges: Threat Explorer can search up to 30 days of data. Real-time detections is limited to 7 days.
5. Permissions Required: Search and Purge role is needed to delete emails. Security Reader can view but not remediate.
Common Exam Scenarios:
- When asked about finding all users who clicked a malicious link, the answer involves Threat Explorer with URL click data - For bulk remediation of phishing emails, use Threat Explorer to identify and then take action - Questions about automated response to threats point to AIR capabilities - Campaign identification questions relate to the Campaigns view
Watch For:
- Questions that mix Defender for Office 365 with Defender for Endpoint features - Scenarios requiring specific licensing (Plan 1 vs Plan 2 vs Microsoft 365 E5) - Integration questions with Microsoft Sentinel or the unified security portal - Time-based constraints that affect which tool can retrieve historical data