Top 5 Microsoft 365 Security Gaps Exposed by Abnormal (and How to Close Them)

Discover the top Microsoft 365 security gaps identified across Abnormal deployments and how Security Posture Management helps close them.

Abhishek Anbazhagan

February 18, 2026

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4 min read

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Security posture management is more than a compliance exercise. It determines whether a single misconfiguration becomes a headline or remains contained.

Security posture data from Abnormal deployments reveals a consistent pattern: a small set of misconfigurations recurs across tenants. They are easy to overlook, yet common enough to allow attackers straightforward paths to persistence and privilege. What seems routine for administrators becomes valuable for attackers who depend on predictable access behavior.

The findings below reflect the misconfigurations observed most frequently across Abnormal tenants. Together, they highlight the core areas where configuration drift creates risk inside Microsoft 365.

The Most Common Misconfigurations in Microsoft 365

Abnormal’s posture data highlights several misconfigurations that occur at high frequency across tenants. The following posture gaps represent the largest sources of cloud email security exposure observed across the customer base.

Rank

Posture

Why It Matters

How to Fix

1

Application with High-Risk Permissions Without User Sign-Ins

High-risk permissions granted to apps with no recent user sign-ins and limited oversight create silent access paths for attackers. This gap appears more frequently than any other finding.

Review app permissions and revoke unused or unverified access in the Microsoft 365 admin center.

2

Customer Lockbox Not Enabled

Without Customer Lockbox, support interactions may allow broader access to content than necessary. Although it is a standard safeguard, many tenants still leave it disabled.

Enable Customer Lockbox in the Microsoft 365 admin center.

3

Dynamic Group for Guest Users Not Created

Guest users accumulate across collaboration platforms. Without a dynamic group, they remain untracked and can expand without guardrails.

Create and maintain a dynamic group for all guest accounts.

4

No Sign-In Frequency Enforcement and Persistent Browser Sessions for Administrators

Administrative sessions remain active for extended periods, increasing exposure to session hijacking and stale tokens.

Require strict sign-in frequency and non-persistent sessions for admin roles.

5

Admin Center Access Not Limited to Administrative Roles

Many tenants allow users outside administrative roles to retain access to high-level controls. This expands the effective attack surface.

Restrict admin center access to active administrators only.

These findings reveal a clear pattern. Identity controls, access boundaries, and session policies form the backbone of secure cloud email environments. When they drift, risk compounds.

Why These Gaps Matter

Small configuration issues often create the greatest operational risk. They look routine. They blend into everyday administration. Yet they are the precise points where attackers gain footholds with minimal resistance.

A permission that goes unreviewed. A session that never expires. An access setting left broad by default. These are quiet failures that compound over time and create exposure long before anyone notices.

Abnormal highlights these gaps by analyzing how identity controls behave inside Microsoft 365. Each posture finding calls out the specific setting at fault, the impact of leaving it unresolved, and the action required to correct it. This turns scattered configuration details into a clear set of priorities and removes the uncertainty that often slows down remediation efforts.

How Customers Close Gaps

Early Remediation

The posture data shows that once organizations gain clear visibility into these misconfigurations through Abnormal, they move quickly to remediate them. High-severity issues are often resolved within the first two weeks of deployment.

Rapid Climb in Total Fixes

Remediation accelerates as posture findings accumulate and teams systematically address them. In August 2025, customers closed 1,081 posture findings. By November, that number reached 25,627 across participating tenants. That growth reflects two trends occurring simultaneously. More organizations are adopting posture management for the first time, while existing customers remediate larger volumes of findings as they build operational confidence.

Growing Customer Participation

The improvements hold because visibility and monitoring are continuous. Ongoing oversight prevents new misconfigurations from lingering, while contextual explanations help teams understand why each issue matters.

The number of organizations contributing to these posture improvements grew from 472 in August 2025 to 2,060 in November. The expansion is driven in part by streamlined remediation workflows. Direct links to Microsoft 365 controls turn guidance into action without disrupting daily operations.

What Misconfiguration Risk Looks Like Across Industries

Industry patterns help clarify where configuration drift is most likely to occur.

Healthcare

Healthcare tenants frequently show missing session controls for administrators. Long-lasting sessions increase risk in environments where clinical systems, vendor tools, and identity platforms intersect. These controls are critical in a sector where sensitive data is widely accessed across distributed care teams.

Financial Services

Financial organizations show recurring findings related to admin center access. When administrative permissions spread across subsidiary units and partner relationships, unnecessary access accumulates. Tightening these boundaries reduces exposure in a sector where strict access control is essential.

Manufacturing

Manufacturing tenants often show gaps in session controls for administrative accounts. Legacy systems and distributed operational technology environments lead to inconsistent identity settings. Persistent sessions create ongoing risk in environments with limited security staffing.

These patterns highlight the value of industry-specific visibility. While the misconfigurations are similar, the operational root causes differ.

Configuration Drift Requires Continuous Attention

Effective posture management is no longer optional; it defines how resilient organizations stay ahead of change. Familiar configuration gaps create ongoing opportunities for attackers. Even the smallest oversight can undermine years of investment in cloud email defenses.

Security Posture Management delivers continuous visibility into configuration risk, enabling teams to close gaps before they can be exploited. Through rapid remediation and sustained alignment, organizations transform posture management from a maintenance task into a measurable security discipline that protects Microsoft 365 environments against everyday drift.

Get a clear view of your own Microsoft 365 configuration risk and see how Abnormal guides remediation at every step.

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Top 5 Microsoft 365 Security Gaps Exposed by Abnormal (and How to Close Them)

February 18, 2026

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