How to Prepare for a Microsoft 365 Security Audit for Microsoft 365
If you’re wondering how to prepare for a Microsoft 365 security audit, you’re definitely not alone. Microsoft 365 (M365) sits at the center of most modern businesses, holding email, documents, Teams chats, and often very sensitive customer data. That makes it a prime target—and honestly, sometimes an easy one—if security and compliance haven’t been taken seriously.
An m365 security audit is basically a structured health check of your environment. It looks at how well you’re managing identities, protecting data, controlling devices, and dealing with third‑party apps. It also checks how closely you align with best practices such as the CIS Benchmark Microsoft 365 guidance and other standards.
This guide walks through, step by step, how to get ready. We’ll focus on practical, no-nonsense actions you can take before an auditor (internal or external) shows up, and how to turn this into an ongoing Microsoft 365 compliance program rather than a once‑a‑year panic exercise.
Understand the Shared Responsibility Model in Microsoft 365
Before you touch any settings, you need the right mental model. A surprising amount of audit pain comes from assuming “Microsoft handles security for us.”
In reality, Microsoft 365 uses a shared responsibility model:
- Microsoft secures the infrastructure: data centers, physical servers, networks, base platform.
- You (the customer) secure your identities, data, and configurations: who can log in, what they can see, how long you keep data, how you share it, and which apps you trust.
If you think of Microsoft 365 as a fortress, Microsoft builds the walls and keeps the roof from leaking. You’re still responsible for locking the doors, checking who gets keys, and making sure there isn’t a wide‑open window called “Anyone with the link can view.”
Going into an m365 security assessment with that mindset is key. Auditors will look not just at whether you’ve turned on certain features, but whether you’re actively managing your side of the responsibility equation.
What auditors actually care about
Most Microsoft 365 compliance or security audits will zoom in on a few core dimensions:
- Identity and access – Are accounts protected (especially admins)? Are you using multi‑factor authentication (MFA) properly? Is role-based access limited and controlled?
- Data protection and sharing – Are SharePoint, OneDrive, and Teams configured to prevent oversharing? Are sensitive folders locked down? Do you track who has access to what?
- Device security – Are laptops, phones, and tablets accessing M365 properly secured? Is there a policy for lost or stolen devices?
- Third‑party apps and integrations – Which apps have access to your tenant? What permissions do they have? Are they actually necessary?
- User awareness and process – Do users know how to avoid phishing, use strong passwords, and handle sensitive info? Do you have written policies, or is it just “tribal knowledge”?
When you prepare for a Microsoft 365 security audit, you’re basically putting your house in order across all of these, ideally before someone arrives with a checklist.
Linking to CIS Microsoft 365 Foundations
To make this less abstract, many auditors (or security partners) align their reviews with the CIS Microsoft 365 Foundations Benchmark. This is a set of 129 controls spelling out what “good” looks like in an M365 tenant.
You’ll see language like:
- CIS Benchmark Microsoft 365 Level 1 – essential, low‑impact hardening (turning on MFA, basic logging, safer defaults).
- Level 2 – enhanced protections for higher‑risk environments (tighter access, more restrictive sharing, stricter device and app controls).
You don’t need to memorize every CIS control, but knowing it exists—and ideally mapping your settings to it—will make your m365 security audit preparation much smoother. It’s also a strong foundation for broader microsoft 365 compliance efforts (SOC 2, ISO 27001, NIS2, etc.).
Lock Down Identities: Accounts, Passwords, and MFA
To be blunt, most real‑world breaches in Microsoft 365 don’t start with some ultra‑fancy exploit. They start with a stolen password. So if you want quick, high‑impact wins before your audit, start with identities.
Enforce strong passwords and unique logins
Auditors will look for weak password policies and bad habits like shared accounts.
Actions to take:
- Review your password policy in Azure AD / Entra ID:
- Ban common passwords.
- Enforce minimum length and complexity.
- Configure password protection for hybrid environments if relevant.
- Eliminate shared accounts where possible. Shared “info@company” mailboxes are fine, but the underlying identities should be unique per person and properly assigned.
- Discourage password reuse across systems. Some organizations back this up with security awareness training or password manager guidance.
It sounds obvious, but auditors still routinely find “Password123” accounts and sticky notes on monitors. That’s the sort of thing that turns a routine m365 security audit into an uncomfortable one.
Enable and optimize multi‑factor authentication
A recurring theme in the transcript was multi‑factor authentication (MFA)—and for good reason. It’s one of the single most effective controls you can implement.
For Microsoft 365, consider:
- Turn on MFA for all users, starting with:
- Global admins and privileged roles
- External users with elevated access
- Anyone accessing sensitive data (finance, HR, customer data)
- Choose stronger MFA methods:
- Move away from SMS where you can (because of SIM swapping risk).
- Prefer authenticator apps (Microsoft Authenticator, etc.).
- For high‑risk roles, consider hardware security keys (FIDO2) as the gold standard.
- Use Conditional Access policies to enforce MFA based on risk:
- Require MFA for sign‑ins from unknown locations or unmanaged devices.
- Block legacy authentication that bypasses modern MFA.
Auditors will often check:
- How many accounts don’t have MFA enabled.
- Whether break‑glass (emergency) accounts are secured and monitored.
- Whether there’s a formal policy covering MFA expectations.
If you haven’t already, make “enable MFA everywhere” your day‑one preparation step. It’s low friction compared with the amount of risk it removes.
Get Control of Data Sharing in SharePoint, OneDrive, and Teams
One of the most painful (and common) findings during a Microsoft 365 security audit is oversharing: sensitive files that are accessible far beyond the people who actually need them.
Because Microsoft 365 makes collaboration so easy, it’s also very easy to accidentally leak your “digital crown jewels” through SharePoint, OneDrive, or Teams. Auditors will absolutely test this area.
Review external and anonymous sharing settings
Start at the tenant level:
- In the SharePoint and OneDrive admin centers, review your default sharing settings:
- Do you really need “Anyone with the link can view” across the board?
- Can you restrict external sharing to specific domains (trusted partners)?
- Should external sharing be disabled outright for certain sites or libraries?
Key preparation steps:
- Identify high‑risk sites (finance, HR, legal, executive, R&D) and apply stricter sharing policies.
- Disable anonymous links for sensitive locations; require authenticated external users instead.
- Set expiration and access review policies for guest access where possible.
In an audit, a common scenario is: the assessor picks a sensitive SharePoint library and checks who can access it. You want that answer to be boring and tightly controlled, not “technically anyone in the company could see all client financials.”
Map who has access to what (and clean it up)
This is where many organizations struggle because they simply don’t have visibility. Over time, folders get shared, Teams get created, and the web of permissions becomes hard to reason about.
To prepare:
- Inventory access to critical data locations:
- High‑value SharePoint sites
- Key Teams (executive, board, M&A, client projects)
- Sensitive OneDrive folders shared broadly
- Remove stale or unnecessary access, especially for:
- Former employees (check for orphaned OneDrive content)
- Old vendors or guests
- Over‑broad groups like “Everyone” or “All employees” on sensitive content
If you’re aligning with CIS Benchmark Microsoft 365 and aiming for a more formal microsoft 365 compliance posture, this type of permission review isn’t just nice to have; it’s expected.
Over time, you’ll likely want to formalize this into an m365 compliance checklist item: quarterly or semi‑annual access reviews for sensitive locations. Auditors love to see that kind of regular governance instead of one‑off cleanups right before they arrive.
Harden Devices and Third‑Party Applications
Another major theme from the transcript was that risk doesn’t live only in the cloud portal. Laptops, phones, and third‑party apps are often the soft underbelly of a Microsoft 365 environment.
Secure devices that access Microsoft 365
If a laptop with cached credentials or synced OneDrive files is stolen, an attacker may not need to “hack Microsoft 365” at all—they just open the device.
To prepare for a Microsoft 365 security audit:
- Require device protection for corporate endpoints:
- Full‑disk encryption (BitLocker for Windows, FileVault for macOS).
- Strong device login passwords or biometrics.
- Automatic screen lock and inactivity timeouts.
- Use Intune or another MDM solution (where possible) to:
- Enforce baseline configuration profiles.
- Block jailbroken / rooted devices.
- Remotely wipe lost or stolen devices.
- Make sure you have a documented lost/stolen device process (who to notify, what steps to take, how quickly).
In an audit context, even simple documentation like “We require BitLocker on all Windows laptops and verify compliance monthly” goes a long way to showing you take device security seriously.
Audit and rationalize third‑party app access
Every third‑party app connected to Microsoft 365 is a potential new door into your data. The transcript mentioned a real breach caused by a vulnerable time‑tracking app that had broad access to emails and files—this is not hypothetical.
Before your m365 security audit:
- List all OAuth apps and Enterprise Applications in your tenant.
- For each app, check:
- What permissions it has (Mail.Read, Files.Read.All, etc.).
- Who consented to it (admins vs users).
- Whether it’s still in use and by whom.
- Remove or disable apps that are:
- Unused
- Duplicative
- From vendors you no longer trust or use
Then, tighten the front door:
- Consider restricting user consent so that only admins can approve apps with high‑impact permissions.
- Create a simple vetting process: security review, data protection assessment, and sign‑off before new apps are granted wide‑ranging access.
Auditors will often pick a random third‑party app and ask, “Why does this need this level of access?” You want a clear, documented answer—not confused shrugs.
Strengthen People, Policies, and Continuous Compliance
Technology alone won’t get you through a Microsoft 365 audit. In many cases, what really differentiates a mature environment is how well people are trained and how structured your ongoing processes are.
Build a basic security awareness program
The transcript spent a fair amount of time on the “human element,” and rightly so. Even the best Microsoft 365 security configuration can be undone by someone clicking the wrong phishing link.
Ahead of your audit:
- Run or refresh security awareness training for staff, covering:
- How to recognize phishing and social engineering.
- How to create and store strong passwords.
- Why oversharing files is risky.
- What to do if they suspect an incident.
- Repeat this training regularly (at least annually) and track attendance.
During a m365 security assessment, auditors may ask for evidence of:
- Training materials or provider details.
- Attendance logs.
- Phishing simulation results (if you run them).
To be honest, this doesn’t have to be fancy—what matters is that it’s real, repeatable, and taken seriously by leadership.
Document your policies and automate where you can
If it’s not written down, auditors will often treat it as “not really happening.” Documentation and automation go hand‑in‑hand here.
Useful documents to have ready:
- Access control policy for Microsoft 365 (who gets what and how).
- Password and MFA policy (what’s required, how exceptions are handled).
- Data classification and sharing policy (what’s sensitive, where it can live, and how it can be shared).
- Third‑party app review process.
- Incident response playbook for M365‑related incidents.
On the automation side, consider how you’ll keep this all from drifting over time. Configuration drift is one of the quiet killers of microsoft 365 compliance—things start secure and slowly loosen as new features, teams, and apps are added.
Use Automation and Benchmarks to Stay Ready (Not Just Get Ready)
Preparing for a single Microsoft 365 security audit is one thing. Staying ready, month after month, is another challenge entirely. That’s where using formal benchmarks and automated assessment tools can really change the game.
Leverage CIS Benchmark Microsoft 365 for structure
Instead of inventing your own standard, it’s smart to align with a widely recognized one like the CIS Benchmark Microsoft 365 Foundations.
Benefits:
- Gives you a concrete, detailed m365 compliance checklist across 129 controls.
- Helps you distinguish between Level 1 (essential) and Level 2 (enhanced) protections.
- Provides a common language for conversations with auditors, management, and external partners.
If you’re pursuing broader certifications like SOC 2 or ISO 27001, using the CIS Microsoft 365 Foundations benchmark as your baseline helps avoid duplication and demonstrates a structured approach to platform hardening.
Automate your Microsoft 365 compliance assessments
Manually checking every CIS control or re‑reviewing hundreds of settings before each m365 security assessment is painful—and, frankly, prone to human error.
This is where microsoft 365 compliance automation tools are genuinely helpful. Solutions like ConfigCobra continuously check your tenant against the CIS Benchmark Microsoft 365 and related standards.
Using ConfigCobra, you can:
- Automatically assess all 129 CIS Microsoft 365 Foundations Benchmark controls.
- Track Level 1 and Level 2 profiles separately (essential vs enhanced).
- Run scheduled assessments (daily, weekly, monthly) to catch configuration drift early.
- Generate audit‑ready PDF reports with evidence and prioritized remediation steps.
- Map CIS controls to multiple frameworks (NIS2, HIPAA, PCI DSS, ISO/IEC 27001, NIST CSF, GDPR, SOC 2, etc.).
- Collaborate as a team with role‑based access and clear ownership of remediation tasks.
In my experience, this turns the question from “How do we scramble for the next audit?” into “How do we show our auditor that we’re continuously monitoring and improving?”
If you’re serious about automated compliance m365 and want an ongoing view of your risk posture instead of a snapshot, it’s worth looking at tools in this space. You can see how ConfigCobra approaches this here:
https://configcobra.com/use-cases
Preparing for a Microsoft 365 security audit doesn’t have to be a terrifying experience. If you break it down into clear steps—securing identities with strong passwords and MFA, tightening data sharing in SharePoint, OneDrive, and Teams, hardening devices and apps, and investing in user awareness—you’ll already be ahead of many organizations.
The key shift is to stop thinking of an audit as a one‑off event and start treating it as a checkpoint in an ongoing security journey. Using structured guidance like the CIS Benchmark Microsoft 365 Foundations and reinforcing that with microsoft 365 compliance automation means you’re not just “passing the test,” you’re actually reducing real‑world risk.
If you want help moving from manual spot‑checks to continuous, automated m365 compliance assessment, take a look at how ConfigCobra supports CIS‑aligned Microsoft 365 security audits, reporting, and remediation:
https://configcobra.com/use-cases
Put the basics in place, automate what you can, and make regular reviews part of your operational rhythm. That way, when the next Microsoft 365 security audit comes around, you’re not scrambling—you’re just showing the evidence of work you’re already doing to protect your digital crown jewels.