Microsoft Sentinel, advanced email protection policies

In Microsoft Sentinel, you can implement advanced email protection policies to enhance security and prevent threats like phishing, spam, and malware in emails. Although Sentinel does not directly manage email filtering, it integrates with other Microsoft 365 Defender services (like Microsoft Defender for Office 365) to monitor and respond to email security threats.

Here’s a step-by-step guide to implementing advanced email protection policies with Microsoft Sentinel:

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Step 1: Integrate Microsoft Defender for Office 365 with Microsoft Sentinel

1. Navigate to Microsoft Sentinel:
   • In the Azure portal, go to Microsoft Sentinel.
   • Choose your Sentinel workspace.
2. Enable Microsoft 365 Defender Integration:
   • Go to Data Connectors under the Configuration section.
   • Search for Microsoft Defender for Office 365.
   • Select the connector and click Open connector page.
   • Follow the steps to connect Microsoft Defender for Office 365 to your Sentinel workspace. This typically requires:
     • Microsoft 365 global administrator permissions.
     • Access to the Microsoft Defender portal for Office 365.
   • Ensure that email traffic is being monitored and logged into Sentinel.

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Step 2: Configure Defender for Office 365 Protection Policies

You will configure email protection policies in Microsoft Defender for Office 365, which will then feed data into Microsoft Sentinel for monitoring and alerting.

A. Anti-Phishing Policies

1. In the Microsoft 365 Defender portal, go to Email & Collaboration.
2. Under Policies & Rules, choose Threat policies.
3. Select Anti-Phishing and click + Create policy.
4. Define the following settings:
   • Policy Name: Choose a descriptive name (e.g., “Phishing Protection Policy”).
   • User Actions: Specify actions for the system to take on suspicious emails (e.g., quarantine, delete).
   • Targeted Users: Define the users or groups that this policy applies to.
   • Phishing Thresholds: Set thresholds for triggering phishing actions.

B. Anti-Spam Policies

1. Go to Microsoft Defender for Office 365 > Policies > Anti-Spam policies.
2. Create or modify an anti-spam policy to:
   • Set filtering rules for different spam classifications.
   • Configure actions like quarantining or blocking emails based on the detected spam score.

C. Safe Links & Safe Attachments Policies

1. In the Defender portal, navigate to Threat policies.
2. For Safe Links:
   • Configure policies to protect against malicious links in emails.
   • Set actions such as blocking or rewriting URLs in suspicious emails.
3. For Safe Attachments:
   • Configure to block attachments with malicious payloads or automatically detonate them in a sandbox environment to evaluate potential risks.

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Step 3: Monitor Email Security Alerts in Microsoft Sentinel

Once Defender for Office 365 policies are in place, email security-related logs and alerts will be ingested into Sentinel. You can create customized monitoring solutions to detect, investigate, and respond to email threats.

1. Check for Ingested Email Data:
   • In the Sentinel Logs section, run queries to check for email-related data:

     EmailEvents
     | take 10
     

   • Look for specific event types like phishing attempts, spam detection, or blocked attachments.
2. Create Alerts for Suspicious Emails:
   • In Analytics, create custom rules to alert you about specific email threats:
     • Alerts for blocked phishing emails.
     • Alerts for users who receive a high volume of spam.
     • Alerts for users who click on suspicious links or open malicious attachments.

   Example KQL query for suspicious email detection:

   EmailEvents
   | where ActionType == "PhishDetected" or ActionType == "MaliciousAttachment"
   | summarize count() by UserPrincipalName, ActionType, Timestamp
   

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Step 4: Automate Response Using Playbooks

You can automate responses to detected threats by creating playbooks in Azure Logic Apps. For instance, you can automatically:

• Quarantine suspicious emails or block the sender.
• Open a ticket for further investigation in a ticketing system like ServiceNow.
• Send alerts or email notifications to admins.

1. Go to Playbooks in the Sentinel portal.
2. Click + Create to start a new playbook using a template or build from scratch.
3. Integrate with actions like Defender for Office 365 to manage email quarantines.

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Step 5: Review and Update Policies

Regularly review the performance of your email protection policies:

• Refine Anti-Phishing and Anti-Spam settings to adjust sensitivity based on emerging threats.
• Update Safe Links/Attachments policies to include new threat intelligence or adapt to new phishing techniques.
• Use incident investigation and hunting in Sentinel to analyze email security incidents over time.

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Step 6: Leverage Microsoft Sentinel Dashboards

To enhance visibility and improve incident response:

1. Use Workbooks in Sentinel to create custom visual dashboards for email threats.
   • Pre-built dashboards for Microsoft Defender for Office 365 can show metrics like phishing attempts, spam activity, and malware detections.
2. Review these dashboards regularly to identify trends and areas needing attention.

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By combining Microsoft Defender for Office 365 policies and Microsoft Sentinel, you can achieve a powerful layer of email security that detects, investigates, and responds to threats efficiently.

Let me know if you need help with specific policies or creating custom queries!