M365 Security Overview

Microsoft 365 can provide a strong security foundation, but only if the right licences are in place and the tools are actually used (so IT has set things up properly). This post provides a practical overview of the security capabilities that come with Microsoft 365 Business licences and explains why Microsoft 365 Business Premium is the minimum starting point we recommend for most organisations.

The aim is to help business owners and information workers better understand what is available and why it matters.

Microsoft 365 Business licences – security at a high level

Microsoft offers many different Business plans for organisations, we are focussed here on comparing Microsoft 365 Business Premium with the two we commonly encounter when we are called on to engage or fix a customer’s tenant:

• Microsoft 365 Business Basic
• Microsoft 365 Business Standard
• Microsoft 365 Business Premium (our go to license)

They all deliver productivity tools, but the differences in security capability are significant.

Microsoft 365 Business Basic

Business Basic includes Exchange Online, Teams and web‑based Office apps.

From a security perspective, it provides:

• Basic spam and malware filtering for email
• Basic identity protection
• Multi‑factor authentication support

What it does not provide is any meaningful control over user devices. There is no central device management, no advanced endpoint protection and very limited ability to enforce security standards.

Business Basic is cheap but you get what you pay for and with security being such a big deal for any modern office we don’t recommend anything less than Microsoft 365 Business Premium.

Microsoft 365 Business Standard

Business Standard adds the desktop Office apps and improved collaboration tools.

Security, however, remains largely unchanged from Business Basic:

• No endpoint detection and response
• No device compliance enforcement
• No ability to centrally harden laptops and mobiles

Business Standard improves how people work and simply brings Desktop Apps to the table, it doesn’t improve how well the organisation is protected.

Microsoft 365 Business Premium

Business Premium is where Microsoft 365 gains a genuine security edge.

In addition to everything in Business Standard, it introduces many security layers including:

• Microsoft Defender for Business
• Microsoft Intune for device management
• Stronger identity and access controls
• The ability to enforce security policies across users and devices

This shift from optional to enforced controls is the key difference.

Defender for Business: protecting devices properly

Microsoft Defender for Business is included with Business Premium and provides enterprise‑grade endpoint protection designed for small and medium businesses.

At a high level, this includes:

• Next‑generation antivirus and anti‑malware
• Behaviour‑based threat detection
• Ransomware protection and containment
• Central visibility across Windows, macOS and supported mobile devices

The reality is that users will click on things, even with the best training. Defender for Business assumes this and focuses on limiting impact, detecting abnormal behaviour early, and allowing response before damage spreads.

This is a step change from traditional antivirus tools that rely on known signatures and hope nothing new appears.

Defender threat policies: email remains a primary risk

Email is still one of the most common attack vectors, particularly for phishing, impersonation and credential theft.

Business Premium allows Defender threat policies to be properly configured and enforced across:

• Phishing and spoofing attempts
• Malware attachments
• Dangerous links
• Executive and domain impersonation

While all plans include baseline email protection, Business Premium enables policies to be tuned to real‑world usage rather than left in default mode. This is particularly important for finance teams, executives and anyone handling sensitive information.

Intune: device security that is consistent and enforceable

One of the most important inclusions with Business Premium is Microsoft Intune.

Intune allows organisations to manage and secure company laptops and mobile devices, rather than relying on users to “do the right thing”.

From a security perspective, Intune enables:

Local Administrator Password Solution (LAPS)

Intune can automatically manage and rotate local administrator passwords on devices. This removes a common weakness where the same admin password exists across multiple machines.

Attack Surface Reduction (ASR) rules

ASR rules restrict risky behaviours such as:

• Office macros launching executable files
• Credential harvesting techniques
• Abuse of built‑in Windows tools

These controls significantly reduce the chance of malware successfully running, even if it reaches a device.

Security baselines

Microsoft security baselines provide hardened configuration standards for devices and users based on current threat models.

Intune allows these baselines to be applied consistently, monitored over time and refined where required. This moves security from being informal to being measurable.

File security: cloud storage vs on‑prem servers and NAS

Many businesses still rely on on‑prem file servers or NAS devices because they are familiar and appear simple.

From a security and resilience perspective, they come with real drawbacks:

• Patch management is often manual or inconsistent
• Access controls are coarse and difficult to audit
• Backups may exist but are rarely tested
• Remote access increases attack surface
• They are costly to maintain and replacing hardware when the warranty expires adds projects and lifecycles you don’t have to deal with when you move your workloads to the cloud

By contrast, storing files in Microsoft’s cloud (SharePoint and OneDrive) provides:

• Strong identity‑based access control
• Built‑in versioning and recovery
• Continuous monitoring and auditing
• Protection against many ransomware scenarios
• Data hosted in enterprise‑grade, geo‑redundant data centres

Cloud storage does not eliminate responsibility, but it removes a large amount of undifferentiated heavy lifting that many businesses are not resourced to handle well.

Microsoft 365 is the core, not the whole story

Microsoft 365 Business Premium forms the security backbone for most modern workplaces, but it is not the only consideration.

A sound security posture also includes:

• Domain security: correctly configured SPF, DKIM and DMARC to reduce email spoofing and impersonation risk
• Password management: removing password reuse and improving visibility through a proper password manager
• User awareness training:
  • policies and guidance that reflect how people actually work
  • physhing simulations
  • continuous training and refresher courses

Microsoft Secure Score

Microsoft Secure Score is a simple way for businesses to see how well their Microsoft 365 environment is protected, much like a credit score for security. It looks at how your Microsoft 365 tenant is configured across areas like identities, devices, email, data, and apps, then gives you a score based on how many of Microsoft’s recommended security protections are in place.

A higher score means more best‑practice security controls are enabled and less risk exposure, while a lower score highlights gaps that could be exploited. Importantly, Secure Score doesn’t just show a number—it also provides clear, prioritised recommendations so organisations can steadily improve their security posture over time and track progress in a simple, measurable way.

At Solve Business Services, we benchmark our work against Microsoft’s Secure Score and aim to maintain a score above 70% for our customers. This provides a clear, measurable view of where risk exists and where improvements should be made over time.

Why Business Premium is our baseline recommendation

We recommend Microsoft 365 Business Premium as the foundational licence for the majority of our customers.

Not because it is the most expensive option, but because it:

• Enables consistent security controls
• Allows enforcement rather than reliance on user behaviour
• Provides visibility and accountability
• Creates a solid base to build additional controls on top of

Anything below Business Premium usually results in gaps that need to be filled later with third‑party tools or workarounds.

What’s coming next

The next posts in this series will focus on individual areas such as Defender, Intune and identity protection, using plain language and real‑world examples.

They are intended to be illustrative and practical, not how to guides because your IT (hopefully that’s us) should be looking after these for your business.

How Solve Business Services can help

Solve Business Services works with Australian organisations to design, deploy and manage secure Microsoft 365 environments that are appropriate to their size, industry and risk profile.

If you would like help reviewing your current Microsoft 365 setup, understanding your licensing, or improving your security posture, you can reach us via solvebusiness.au or contact us directly to arrange a discussion.

Getting the foundations right makes everything else simpler.