Microsoft 365 has become the backbone of how many organisations communicate, collaborate and store information. Email, Teams, SharePoint and OneDrive now sit at the centre of day-to-day operations for businesses of all sizes.
But while Microsoft provides a powerful and secure platform, protecting your organisation’s data within it is a shared responsibility.
Many security risks don’t come from sophisticated cyber-attacks. They come from simple configuration gaps, legacy settings or features that haven’t yet been fully enabled.
The good news is that meaningful improvements to Microsoft 365 security don’t require complex transformation projects. In many cases, a small number of practical steps can significantly reduce risk.
Here are five areas organisations should prioritise.
1. Enable multi-factor authentication for all users
Multi-factor authentication (MFA) remains one of the most effective ways to prevent unauthorised access to business systems.
Even when passwords are compromised through phishing attacks or data breaches, MFA provides an additional verification step that blocks most attackers from gaining access.
Despite this, many organisations still operate with incomplete MFA coverage across accounts, particularly for legacy users, shared mailboxes or administrator roles.
There are several different ways MFA can be implemented, ranging from authenticator apps to hardware security keys and Conditional Access policies that apply protection based on location, device type or risk level. Choosing the right approach depends on how your organisation works day to day, and selecting a method that balances security with usability is key to ensuring adoption across teams.
It is also worth noting that Basic and Standard licensing on most platforms (including Microsoft 365) typically does not include full Conditional Access capability. For organisations using these licence levels, there is an important decision to make: balancing the cost of Premium licensing against the very real risk of cyber compromise.
However, many organisations already have Conditional Access available through licences such as Microsoft 365 Business Premium but have not yet configured policies to their full potential. In practice, this is often where some of the most valuable security improvements can be made quickly.
Ensuring MFA is enabled consistently across all users is one of the fastest ways to strengthen security immediately.
2. Review administrator access and permissions
Administrative accounts provide powerful control across Microsoft 365 environments. They also represent a high-value target for attackers.
Over time, organisations often accumulate more administrator accounts than they need, with permissions that extend beyond current responsibilities.
A simple review can help ensure:
- only necessary administrator roles remain active
- permissions follow the principle of least privilege
- privileged access is monitored appropriately
- legacy administrative accounts are removed
Reducing unnecessary privilege levels significantly lowers the impact of potential compromise.
3. Strengthen email protection settings
Email remains the most common route for cyber incidents affecting organisations.
Microsoft 365 includes built-in protections against phishing, malicious attachments and impersonation attacks, but these controls are not always configured to their full potential.
Improving email security settings can help:
- reduce phishing exposure
- prevent malicious links reaching users
- block suspicious attachments automatically
- protect senior staff from impersonation attempts
Advanced protections can also provide real-time scanning of links and attachments, helping to identify threats that only become malicious after an email has been delivered. In addition, implementing targeted protections for high-risk users, such as finance teams or senior leadership, can significantly reduce the likelihood of successful impersonation or payment fraud attacks.
Small configuration adjustments in this area can prevent a large proportion of real-world incidents.
4. Protect data with sensible sharing controls
Microsoft 365 makes collaboration easy, internally and externally. But without appropriate controls, information can sometimes be shared more widely than intended.
Reviewing sharing settings across SharePoint, Teams and OneDrive helps organisations balance flexibility with protection.
This typically includes:
- managing external sharing permissions
- limiting anonymous access links
- setting appropriate defaults for file visibility
- ensuring sensitive information remains controlled
Clear sharing policies help staff collaborate confidently while protecting business data.
5. Turn on audit logging and security alerts
Many organisations already have valuable security insight available within Microsoft 365 but aren’t actively using it.
Audit logging and alerting tools allow organisations to:
- detect unusual login behaviour
- identify suspicious activity patterns
- monitor permission changes
- respond quickly to potential incidents
These features improve visibility and help organisations move from reactive support to proactive protection.
A practical starting point for stronger security
Improving Microsoft 365 security doesn’t require major disruption or complex technical change.
In most environments, reviewing identity protection, administrator permissions, email security settings, sharing controls and audit visibility provides a strong foundation for reducing risk quickly and effectively.
As cyber threats continue to evolve, organisations that regularly review how their Microsoft 365 environment is configured are better positioned to protect their users, safeguard their data and maintain operational confidence.
Security is rarely about one large project. It’s about making the right small decisions consistently over time.