Microsoft 365 Security Hardening
A technical design consultancy wanted to improve the security of its Microsoft 365 and Defender environment systematically. The goal was to reduce the attack surface, strengthen identity protection, improve endpoint hardening and increase visibility into risks in the environment.
Microsoft Secure Score was used as a technical metric, but not as a goal in itself. The more important objective was to understand which recommendations genuinely reduce risk and which changes require testing before wider deployment.
At the starting point, several protective services were already in use in the Microsoft environment, but the aim was to develop settings, findings and recommendations in a controlled way. It was especially important to consider usability in design, automation and remote work environments.
The work helped raise the security of the Microsoft 365 environment to a clearly stronger level without applying hardening measures blindly at the expense of everyday work.
Key areas
- Microsoft Secure Score development
- Assessment of the current state of Microsoft 365 security
- Defender for Endpoint protection
- Development of Defender for Identity visibility
- Intune and endpoint management
- Strengthening email and phishing protection
- Risk-based implementation and follow-up
What was done
The work reviewed Microsoft Secure Score and Defender recommendations and implemented key security improvements in practice. The aim was to bring Microsoft 365 settings more up to date and better aligned with modern security practices.
The work covered, among other things:
- protecting identities and administrative accounts
- improving Defender visibility
- hardening Entra ID and Active Directory environments
- endpoint and server protection settings
- strengthening email and phishing protection
- reviewing Office and cloud service sharing settings
- developing Intune and Defender settings
- restricting outdated or high-risk practices
- monitoring findings and prioritising further development
Changes were assessed from a risk-based perspective so that security could be strengthened without unnecessarily disrupting everyday technical workflows.
Technical approach
The technical approach was based on reviewing the overall security of the Microsoft 365 environment. Secure Score was used as a metric, but decisions were made based on risk.
The key principles were:
- first, visibility and understanding the findings
- then, assessing the impact
- after that, controlled implementation
- finally, follow-up and further development
The environment was reviewed from several perspectives:
- identity and access management
- endpoints and servers
- email and phishing protection
- cloud service sharing
- Defender and Sentinel visibility
- third-party application permissions
- usability in technical design work
In this work, every change had to be considered in relation to how the organisation works, how information is shared with customers and how design environments remain operational.
Controlled prioritisation
Recommendations were not implemented automatically. Changes were assessed based on risk, impact and usability.
Controlled implementation
Hardening measures were introduced step by step so that their impact on endpoints, users and design environments could be taken into account.
Continuous monitoring
Secure Score and Defender findings supported monitoring, but the actual goal was to create a more sustainable operating model for developing security.
Outcome
During the project, Microsoft Secure Score increased clearly, from around the mid-70% range to over 90%. Even more importantly, the key security settings of the environment were reviewed systematically and from a risk-based perspective.
The concrete impact of the work was visible in reduced identity risks, stronger endpoint protection, improved phishing protection, more controlled sharing and better visibility into the security posture of the Microsoft 365 environment.