Configure Defender for Endpoint security policies and ASR rules
5 minutes
5 Questions
Microsoft Defender for Endpoint security policies and Attack Surface Reduction (ASR) rules are essential components for protecting enterprise environments from threats. Security policies in Defender for Endpoint are configured through the Microsoft 365 Defender portal or Microsoft Endpoint Manager …Microsoft Defender for Endpoint security policies and Attack Surface Reduction (ASR) rules are essential components for protecting enterprise environments from threats. Security policies in Defender for Endpoint are configured through the Microsoft 365 Defender portal or Microsoft Endpoint Manager (Intune). These policies define how endpoints are protected, monitored, and respond to threats. To configure security policies, administrators navigate to Settings > Endpoints > Configuration Management. Here, you can establish policies for antivirus settings, firewall configurations, and endpoint detection and response (EDR) capabilities. Policies can be applied to device groups based on tags, domains, or other organizational criteria. ASR rules specifically target behaviors commonly exploited by malware and malicious applications. These rules reduce the attack surface by blocking suspicious activities before they execute. Configuration occurs through Group Policy, PowerShell, or Microsoft Endpoint Manager. Key ASR rules include blocking executable content from email clients, preventing Office applications from creating child processes, blocking credential stealing from the Windows local security authority subsystem, and preventing JavaScript or VBScript from launching downloaded executable content. When implementing ASR rules, administrators should start with audit mode to assess potential impact on legitimate business operations. This mode logs events that would have been blocked, allowing teams to identify false positives. After validation, rules can be switched to block mode for active protection. Best practices include deploying ASR rules gradually, monitoring the Microsoft 365 Defender portal for rule triggers, creating exclusions for legitimate business applications that may trigger rules, and regularly reviewing rule effectiveness. Integration with Microsoft Defender for Cloud allows centralized management across hybrid environments. Security teams should correlate ASR events with other security signals in the unified security operations center for comprehensive threat detection and response capabilities.
Configure Defender for Endpoint Security Policies and ASR Rules
Why It Is Important
Configuring Defender for Endpoint security policies and Attack Surface Reduction (ASR) rules is critical for protecting organizational endpoints from modern cyber threats. These configurations help prevent malware infections, block suspicious behaviors, and reduce the attack vectors that threat actors commonly exploit. For security operations analysts, mastering these settings is essential for maintaining a robust security posture.
What Are Defender for Endpoint Security Policies and ASR Rules?
Defender for Endpoint Security Policies are centralized configurations that define how Microsoft Defender protects endpoints across your organization. These policies control antivirus settings, firewall rules, device control, and endpoint detection and response (EDR) capabilities.
Attack Surface Reduction (ASR) Rules are specific controls that target behaviors commonly used by malware and malicious applications. They block actions like: - Executable content from email clients and webmail - Office applications from creating child processes - JavaScript and VBScript from launching downloaded executables - Credential stealing from the Windows local security authority subsystem (LSASS) - Process creation from PSExec and WMI commands
How It Works
Security policies and ASR rules are managed through multiple interfaces:
1. Microsoft Intune - Primary management portal for endpoint security policies 2. Microsoft Defender Portal - Configuration through Security settings management 3. Group Policy - Traditional on-premises management method 4. PowerShell - Scripted configuration using Set-MpPreference cmdlets
ASR rules can operate in three modes: - Block - Prevents the action and logs the event - Audit - Allows the action but logs it for review - Warn - Shows a warning to users but allows them to proceed
Each ASR rule has a unique GUID identifier, and you can enable specific rules based on organizational needs. The rules integrate with cloud protection and use machine learning to make real-time decisions.
Key Configuration Areas for the Exam
- Endpoint Detection and Response (EDR) policies - Antivirus policies including real-time protection and cloud-delivered protection - Firewall policies and network protection - Attack Surface Reduction rules and their deployment modes - Device control policies for removable media - Exclusions management for legitimate applications
Exam Tips: Answering Questions on Configure Defender for Endpoint Security Policies and ASR Rules
1. Know the management portals - Understand that Intune is the primary tool for managing security policies, while the Defender portal provides additional configuration options.
2. Memorize ASR rule modes - Remember Block, Audit, and Warn modes. Audit mode is recommended for initial deployment to assess impact before blocking.
3. Understand prerequisites - ASR rules require Windows 10/11 Enterprise or Education editions, or Windows Server 2016 or later with proper licensing.
4. Focus on common ASR rules - Know rules that block Office macro abuse, executable content in emails, and credential theft from LSASS.
5. Remember the reporting location - ASR rule events appear in the Microsoft Defender portal under Reports and in Advanced Hunting.
6. Know exclusion best practices - Understand when and how to create exclusions, and that exclusions should be minimized to maintain security.
7. Understand policy precedence - Know how conflicts between Intune policies and Group Policy are resolved.
8. Practice scenario-based thinking - When given a scenario, identify whether the question asks about detection, prevention, or investigation, then select the appropriate policy type.