IT Operations & Cybersecurity Encyclopedia
Microsoft 365 security monthly review checklist
A monthly Microsoft 365 security review helps IT and security teams catch tenant drift before it becomes an incident. The review should capture identity, administrator roles, Secure Score, email protection, guest access, sharing, audit logs, retention, backup, and remediation evidence in a repeatable format.
Monthly reviewIdentity controlsAdmin rolesDefender reviewEvidence tracking
Why it matters
Make Microsoft 365 security review repeatable and evidence-based
Microsoft 365 changes constantly: users join and leave, administrators get added, policies are edited, external sharing expands, Secure Score recommendations change, and alerts may be missed. A monthly review creates a rhythm for finding and correcting drift.
The goal is not to generate a long report nobody reads. The goal is to identify material changes, validate important controls, assign remediation owners, and preserve enough evidence to support management review, audits, and cyber insurance discussions.
This guide is operational planning guidance. It does not replace official Microsoft documentation, cybersecurity audit, incident response, legal/compliance review, or managed IT support agreement.
Practical rule: Every monthly Microsoft 365 security review should produce a dated evidence package, action register, owner list, due dates, exception notes, completed remediation, and executive summary.
Review scope
Monthly review areas
Secure Score and roadmap
Review score movement, high-value actions, completed remediation, deferred actions, and blocked recommendations.
Identity and sign-ins
Check MFA, conditional access, risky sign-ins, failed sign-ins, legacy authentication, and emergency account health.
Privileged access
Review administrator roles, admin changes, partner access, support access, and privileged activity.
Email security
Review Defender policies, phishing trends, quarantine, submissions, Safe Links, Safe Attachments, SPF, DKIM, and DMARC.
Sharing and guests
Review guest users, external sharing, anonymous links, Teams external access, sensitive sites, and stale collaboration.
Evidence and remediation
Close the month with owner assignments, due dates, risk notes, completed actions, and leadership summary.
Review matrix
Microsoft 365 monthly security review matrix
| Area | What to verify | Questions to answer | Evidence |
|---|---|---|---|
| Secure Score | Review score trend, new actions, completed actions, deferred items, license blockers, and priority roadmap. | Are recommended improvements being converted into managed work? | Secure Score snapshot, action register, owner list, and monthly summary. |
| Identity | Review MFA, conditional access, risky sign-ins, legacy authentication, failed sign-ins, and break-glass accounts. | Did identity risk or control drift appear this month? | MFA report, CA change export, sign-in samples, and emergency access test note. |
| Admins | Review privileged roles, Global Administrators, role changes, admin consent, partner access, and support access. | Was administrative access changed or overextended? | Role export, audit logs, admin consent report, and access review notes. |
| Review phishing, malware, quarantine, user submissions, policy changes, Safe Links, Safe Attachments, SPF, DKIM, and DMARC. | Are email threats and controls visible? | Defender report, policy export, submission summary, and DNS authentication records. | |
| Collaboration | Review guests, external sharing, anonymous links, Teams external access, shared channels, and sensitive sites. | Did external collaboration expand beyond intended scope? | Guest export, sharing report, anonymous-link report, and exception list. |
| Recovery and evidence | Review retention changes, backup status, restore tests, incident tickets, unresolved actions, and leadership report. | Can we prove review, remediation, and recovery readiness? | Evidence package, backup report, restore test, ticket list, and executive summary. |
Step-by-step review
Microsoft 365 security monthly review runbook
1
Create the review packet
Start a dated folder or ticket with review scope, tenant name, reviewer, reporting period, evidence checklist, and prior-month open actions.
2
Review identity and admin risk
Check MFA, conditional access, sign-in risk, legacy authentication, break-glass accounts, privileged roles, and admin consent changes.
3
Review email and collaboration exposure
Check Defender for Office 365, mail authentication, phishing trends, quarantine, guest access, external sharing, Teams access, and anonymous links.
4
Review data, retention, and recovery
Check retention changes, sensitivity labels, DLP where used, backup coverage, restore testing, and unresolved recovery risks.
5
Assign remediation
Create action items with owner, due date, priority, evidence required, exception rationale, and escalation path.
6
Report and close
Prepare a concise management summary showing completed work, open risks, blocked items, exceptions, and next-month priorities.
Common risks
Common monthly review gaps
Review without evidence
A meeting note is not enough; keep exports, screenshots, tickets, and decision records.
No owner assignment
Findings become repeated observations when owners and due dates are not assigned.
Admin changes missed
Privileged role changes and admin consent events need monthly visibility.
Guest access ignored
External users and sharing links can expand quickly if collaboration reports are not reviewed.
Backup never tested
Backup status is weaker evidence than a tested restore with validation.
No executive summary
Leadership needs a clear view of material risks, progress, blockers, and decisions.
Related support
Where IT Perfection can help
IT Perfection can help run recurring Microsoft 365 security reviews, maintain evidence, coordinate remediation, and support managed Microsoft 365 operations.
OC Security Audit can help validate Microsoft 365 security evidence, assess control maturity, and prepare audit or cyber insurance readiness findings.
Created by Ali Hassani, CISO
Professional Microsoft 365 monthly security review support
Ali Hassani brings 25+ years of hands-on experience across IT operations, cybersecurity, Microsoft infrastructure, network security, compliance readiness, cloud services, healthcare IT, MSP services, and business technology leadership.
This guide is for initial education and planning. It does not replace a professional cybersecurity audit, compliance assessment, penetration test, legal review, vendor engineering review, or Microsoft professional services engagement.
Monthly review turns configuration into control
A disciplined review cadence improves tenant visibility, remediation ownership, audit evidence, cyber insurance readiness, and executive reporting.
FAQ
Microsoft 365 security monthly review FAQ
What should be checked monthly in Microsoft 365?
Review Secure Score, MFA, conditional access, admin roles, sign-ins, audit logs, Defender for Office 365, guest access, sharing, retention, backup, and open remediation.
Who should own the monthly review?
IT or security should coordinate it, but business owners, compliance, legal, and leadership may own decisions for risk acceptance, retention, exceptions, and funding.
Is a monthly review enough?
Monthly review is a good operational cadence, but high-risk alerts, incidents, administrator changes, and critical vulnerabilities need faster response.
What evidence should be retained?
Keep dated reports, exports, screenshots, log samples, action tickets, exception approvals, restore tests, and executive summaries.
