What is Attack Surface Reduction (ASR)?
Attack Surface Reduction (ASR) is a collection of security controls offered by Microsoft Defender for Endpoint (formerly Microsoft Endpoint Protection). These controls aim to limit the potential attack vectors cybercriminals can exploit on your organisation’s devices. By restricting specific software behaviours commonly abused by malware, ASR helps to mitigate the risk of successful cyberattacks.
How does ASR work?
ASR offers a variety of configurable rules that target software behaviour. Here are some examples:
- Blocking malicious scripts: ASR can block scripts downloaded from the internet or those attempting to download or run additional files.
- Restricting suspicious file execution: ASR rules can prevent applications from launching executable files with suspicious characteristics.
- Limiting email attachments: ASR allows you to control the execution of attachments from emails, reducing the risk of malware hidden in these files.
- Disabling macros: Macros in documents can be exploited by attackers. ASR can disable macros by default, reducing this vulnerability.
Benefits of Attack Surface Reduction:
- Proactive threat defence: ASR takes a proactive approach to security by restricting risky software behaviours before they can be exploited by attackers.
- Reduced risk of malware infection: By limiting malware’s ability to execute or spread on devices, ASR helps to prevent malware infections within your network.
- Improved security posture: Implementing ASR rules strengthens your overall security posture by closing potential attack vectors on your devices.
- Simplified management: ASR rules can be centrally managed and configured through Group Policy or Microsoft Intune, streamlining security management for your IT team.
Use cases with Microsoft Defender for Endpoint:
- Securing Endpoints: ASR is a crucial component of a layered endpoint security strategy with Microsoft Defender for Endpoint, protecting devices from a wide range of cyber threats.
- Mitigating Phishing Attacks: ASR can help prevent malicious attachments or scripts delivered through phishing emails from causing harm on user devices.
- Enhancing Zero-Trust Security: ASR aligns well with a zero-trust security model by minimising potential attack surfaces and enforcing stricter controls on software behaviour.
By implementing Attack Surface Reduction rules with Microsoft Defender for Endpoint, organisations can significantly enhance their device security posture and proactively mitigate cyber threats.
