Avoiding Common Microsoft 365 Security Missteps

15 Aug Avoiding Common Microsoft 365 Security Missteps

Posted at 08:34h in Microsoft 365 by Simon Spencer

Microsoft 365 is a productivity powerhouse. With flexible tools for email, file sharing, collaboration and video meetings, it’s no surprise so many businesses build their entire IT environment around it. But there’s one dangerous assumption many organisations make the moment they move in:

They think it’s secure by default.

And to be fair, that’s an easy assumption to make. After all, this is a Microsoft product, robust, reliable, trusted by millions. If it weren’t safe out of the box, wouldn’t more people be shouting about it?

Here’s the problem. Microsoft 365 absolutely offers the tools to create a secure environment, but it doesn’t automatically activate them in the way most people expect. Its baseline settings prioritise ease-of-use and collaboration, not lock-tight security. And unless you take time to configure, monitor and regularly tweak those settings, you may be exposing your business to more risk than you realise.

Built for ease, not lockdown

Microsoft wants users to get the most out of 365 quickly. Sharing files with colleagues, syncing documents from devices, accessing your email on the go, all of this is intuitive and frictionless. But within that smooth experience lie choices that shape how secure (or exposed) your environment is.

For example, anyone with default global permissions might be able to share files externally without restrictions. Admin accounts might be active without Multi-Factor Authentication (MFA). Legacy protocols, designed before modern attack methods existed, could still be enabled. These aren’t oversights by Microsoft, they’re decisions designed to minimise disruption. But that doesn’t make them safe for your business as they stand.

The most common Microsoft 365 security gaps

Let’s dig a little deeper into specific areas where default settings don’t go far enough. This list isn’t exhaustive, but it highlights just how misleading the word “default” can be when it comes to Microsoft 365.

Weak or inactive MFA

Microsoft recommends that all users, and especially admins, use MFA. Yet many organisations leave this vital layer switched off. The default position is not to enforce it, and unless it’s set up properly, attackers could gain access with little more than a stolen password.

Legacy authentication left on

Many older Office apps support something called ‘legacy authentication’. This method doesn’t support MFA and is a favourite target for brute-force attacks and credential stuffing. Microsoft wants businesses to disable it, but won’t do it automatically, in case it disrupts someone’s workflow.

Overly broad sharing settings

Need to share a file with someone? In the default settings, it’s often easier to send it externally than it is to restrict access. Anyone with the link might be able to view or even edit it. That’s great for getting things done, but a serious gap if sensitive data is being shared unknowingly.

Inactive audit logging

Want to know who’s accessing your data or signing in from unexpected locations? You need audit logs. But in many Microsoft 365 setups, these aren’t switched on from the start. Which means, if something suspicious happens, there’s no record to track it back to its source.

Data loss prevention not configured

The tools are there, data loss prevention (DLP), retention policies, compliance auditing. But in many environments, these aren’t actively configured, or they’re only blanket rules with no nuance. Without tailoring these, your most valuable data could be vulnerable.

Secure Score left unused

Microsoft actually provides a continuously updating Secure Score within your Microsoft 365 dashboard. It benchmarks your configuration and highlights potential weaknesses. But many businesses either ignore it or don’t know where to begin improving the score, and updates stagnate.

Security isn’t a checkbox

By now, a pattern should be emerging. Microsoft 365 offers powerful security capabilities, but they aren’t enabled automatically, and they certainly aren’t tailored to your organisation without some effort. In other words, having the right tools doesn’t guarantee protection.

Security in Microsoft 365 is less about “having” the features and more about “using” them wisely. Licensing gives you access to encrypted sharing, conditional access policies, privileged identity management, device compliance rules and more. But until someone goes in and configures those settings with your business in mind, they don’t offer meaningful protection.

And even once that’s all in place? It needs to be reviewed. Updated. Monitored regularly. Compliance standards change. Threat actors adapt. New features arrive. Security isn’t something you do once, it’s something you build into your operations and revisit often.

Self-managed means self-monitored

Business owners often assume that the secure and efficient running of Microsoft 365 is baked in when they sign up. That’s understandable, it’s marketed as a resilient platform with strong controls. But the day-to-day reality is different.

Email alerts queue up without being read. Logs accumulate with no one reviewing them. Admin teams (or lone IT professionals) struggle to patch every gap, especially when they’re also supporting users, helping with software issues, or setting up new laptops.

This is where risk accumulates, not because people don’t care, but because security often gets crowded out by everything else. It’s no one’s full-time job, so blind spots grow over time.

Strength in support

This is why many SMEs choose to work alongside a trusted IT partner. Not because they can’t manage Microsoft 365 on their own, but because they want someone to tune and maintain it in a way that reflects how they actually work.

A strong IT partner can assess your Microsoft 365 setup using security frameworks, benchmark it against known good practice, and continuously monitor for drift or misconfiguration. They’ll build guardrails that suit your teams, not stifle them. And importantly, they’ll do it without overwhelming you with technical jargon or impractical policies.

Think of it like having a digital facilities manager, someone who makes sure the doors are locked, the lights are working, and nothing suspicious is going on in the background.

Final thoughts

The truth isn’t that Microsoft 365 is insecure. In fact, it offers one of the most secure productivity platforms around, but only when it’s configured, maintained and actively managed for security. That last part is key.

Default settings are designed for accessibility. They make it easier to get started, collaborate with others and move fast. But that same openness creates opportunity for attackers if you’re not keeping a close eye.

If you haven’t reviewed your Microsoft 365 security settings recently, or if you’re not sure how secure your setup really is, now is the time to explore what lies under the hood.