According to official Microsoft Defender for Endpoint documentation, Attack Surface Reduction (ASR) rules are specifically designed to block behaviors commonly used by malware and ransomware, such as malicious macro execution, script downloads from untrusted sources, and the abuse of Office applications to launch harmful executables or exploits.
In this scenario:
* Excel macros downloading scripts from untrusted websites are mitigated by the ASR rule:"Block Office applications from creating child processes" and "Block Office communication application from creating child processes."
* Users opening executable attachments in Outlook are covered by:"Block executable content from email and webmail."
* Outlook rules and forms exploits are addressed by:"Block Office applications from injecting code into other processes." Microsoft's Defender for Endpoint security baseline and documentation highlight that these rules "reduce the attack surface by minimizing the number of entry points an attacker can use to exploit a system." Administrators can configure them through Microsoft Intune, Group Policy, or PowerShell, and monitor their effectiveness in the Microsoft 365 Defender portal under Threat & Vulnerability Management.
Other options like Defender Antivirus (A) focus on detecting known malware after execution rather than blocking risky behaviors preemptively. Windows Defender Firewall (C) controls network traffic, not application-level threats. Adaptive application control in Azure Defender (D) is used for whitelisting applications on Azure VMs, not on Microsoft 365 endpoints.
# Therefore, the correct answer is:
B: Attack surface reduction rules in Microsoft Defender for Endpoint
o365-worldwide