A former staff member still able to read payroll files, an invoice mailbox quietly forwarding emails outside the business, or a director signing in from an unfamiliar country are not unusual problems. An Office 365 security audit is how a business finds these gaps before they become a costly interruption, privacy breach or fraudulent payment.
For many Mackay and regional Queensland businesses, Microsoft 365 has grown one licence, one shared mailbox and one new employee at a time. That is practical in the short term, but it can leave access rules, devices and security settings inconsistent. A proper review brings the environment back under control without making daily work harder than it needs to be.
What an Office 365 security audit actually reviews
Office 365 is now generally called Microsoft 365, but the security questions remain the same. Who can access business data? From which devices and locations? What happens when an account is compromised? Can the business recover critical emails and files?
A useful audit is not a generic scorecard. It examines how your people work, the information they handle and the systems connected to Microsoft 365. A construction business sharing project documents with subcontractors has different risks from a professional services firm holding client records, or a retail business relying on email for supplier invoices.
The review should cover four connected areas:
- identities and user access, including administrator roles, former staff accounts and multi-factor authentication;
- email and collaboration security across Exchange Online, Teams, SharePoint and OneDrive;
- devices, applications and external connections that can reach company data; and
- data protection, recovery arrangements, monitoring and incident response.
The goal is not to switch on every available Microsoft feature. Some controls add cost, administration or friction for users. The right settings depend on your licences, risk profile, workforce and operational requirements.
Start with identities, access and administrator rights
Most Microsoft 365 incidents begin with an identity. A stolen password, a convincing phishing page or a poorly managed administrator account can give an attacker a foothold across email, files and connected cloud services.
An audit should first confirm that every user account belongs to a current person, shared function or approved service. Old accounts should be disabled rather than left available “just in case”. Shared accounts deserve particular attention because they make it difficult to prove who accessed information or approved a change.
Multi-factor authentication should be enforced for all users, with stronger protection for administrators and finance staff. A password alone is no longer adequate protection for a business mailbox. However, implementation needs planning. Staff need a reliable authentication method, clear support during enrolment and an agreed process for lost or replaced mobiles.
Administrator access is another common weak point. Global Administrator rights should be limited to the people who genuinely need them. Day-to-day email and document tasks should not require the same account that can change tenant-wide security settings. The audit should identify privileged roles, confirm they are necessary and review whether dedicated admin accounts are in use.
Check the email controls that stop costly fraud
Email remains the preferred route for phishing, malware and business email compromise. Attackers often do not need to break into a server when they can persuade an employee to disclose a password or alter a bank account detail.
A security review should assess anti-phishing, anti-spam and malware policies, along with quarantine handling. If protection is set too loosely, dangerous messages reach inboxes. If it is set too aggressively, legitimate supplier emails can be delayed or lost. Testing and ongoing adjustment are more useful than assuming the default policy suits every business.
Mailbox forwarding rules deserve close inspection. Criminals who gain access to an account may create hidden rules that forward correspondence to an external address, allowing them to watch invoices and payment conversations. The audit should identify external forwarding, suspicious inbox rules and unexpected mailbox delegates.
Domain protection is also essential. SPF, DKIM and DMARC records help receiving email systems verify whether messages sent in your business name are legitimate. These controls will not stop every impersonation attempt, but they reduce the chance of your domain being used to target customers, suppliers or staff.
Review file sharing without blocking collaboration
SharePoint, OneDrive and Teams make it simple to share information with staff, clients and contractors. That convenience can become a risk when links are open to anyone, never expire, or remain active long after a project finishes.
An Office 365 security audit should check the organisation-wide sharing settings as well as the sites holding sensitive material. It should identify anonymous links, external guests, broad permissions and documents that may be accessible beyond the intended team. Finance, HR, legal and executive folders usually require tighter controls than general project material.
The answer is rarely to turn external sharing off altogether. Regional businesses often work with remote employees, accountants, engineers and suppliers. Instead, set clear rules around who can invite guests, which data can be shared externally, when links expire and how access is reviewed. This keeps collaboration moving while reducing unnecessary exposure.
Include devices, mobiles and connected applications
A well-configured Microsoft 365 tenant can still be undermined by an unmanaged laptop, a lost mobile or a third-party application with excessive permissions. The audit should establish which devices access company email and files, whether they are encrypted and updated, and whether business data can be removed if a device is lost or an employee leaves.
For organisations with company-owned devices, Microsoft Intune can apply consistent security policies, application controls and compliance checks. For bring-your-own-device arrangements, the approach may be lighter. Requiring a screen lock, approved authenticator app and protected work applications can improve security without taking control of a staff member’s personal photos or messages.
Connected applications are often overlooked. Employees may approve a calendar tool, document signing platform, CRM integration or reporting app without realising it has permission to read mailboxes or files. Reviewing application consent and removing unused connections reduces the number of paths into your environment.
Confirm backup, recovery and monitoring arrangements
Microsoft provides strong infrastructure resilience, but that does not automatically mean every deleted or altered business file can be restored to meet your needs. Retention settings, recycle bins and legal hold features each have limits. A dedicated Microsoft 365 backup can provide an additional recovery option for email, OneDrive, SharePoint and Teams data.
An audit should document what is protected, how long it is retained, where backup data is held and who can restore it. More importantly, it should test recovery. A backup that has never been restored is an assumption, not a continuity plan.
Logging and alerting should be reviewed at the same time. The business should be able to investigate unusual sign-ins, significant permission changes, new forwarding rules and administrator activity. Logs are valuable after an incident, but alerts need an owner. There is little benefit in receiving a high-risk notification at 2 am if no one is responsible for responding.
Turn findings into a practical security plan
The output of an audit should not be a technical report that sits unread in a folder. It should prioritise issues by business impact, likelihood and effort to fix. Disabling inactive accounts, enforcing multi-factor authentication and removing unnecessary admin rights are often quick wins. Improving device management, licensing, data classification or backup arrangements may require a staged project.
Good recommendations explain the trade-off. For example, tighter conditional access rules can prevent risky sign-ins, but they need to account for field staff, travel, poor mobile coverage and essential third-party systems. A practical plan protects the business without creating a support burden that staff will work around.
Security is also not a once-only task. New employees, changing roles, new software and evolving threats all alter the environment. Quarterly reviews of privileged access and external sharing, supported by regular staff awareness training, are sensible for many small and medium-sized businesses. Higher-risk organisations may need more frequent monitoring and formal reporting.
EHW Technology can assess Microsoft 365 alongside your devices, connectivity, backup and wider network security, so fixes are considered as part of the whole business environment rather than in isolation.
The most useful next step is to choose a time when an audit can lead directly to action: confirm who owns each finding, set deadlines for high-risk changes and test that staff can still work effectively afterwards. That turns a security review from a compliance exercise into a practical safeguard for the business you have built.