Identity Resilience Strategies for Microsoft 365

Microsoft 365 (formerly Office 365) is the most attacked productivity suite in the world. From Business Email Compromise (BEC) to SharePoint data exfiltration, the threats are constant.

Securing M365 means mastering **Entra ID (Azure AD)**.

The Core Threats

**Legacy Authentication:** Old protocols (IMAP, POP, SMTP) that bypass MFA.

**Illicit Consent Grants:** Phishing attacks that trick users into granting an "OAuth App" access to their email.

**Guest Access Sprawl:** Teams sharing files with external partners and never revoking access.

Step 1: Hardening Authentication

**Disable Legacy Auth:** This is step zero. Turn it off globally.

**Conditional Access Policies:** Implement context-aware access.

*Block* logins from high-risk countries.

*Require* MFA for all users.

*Require* Compliant Devices (Intune) for accessing sensitive SharePoint sites.

Step 2: Tenant Configuration

**Unified Audit Log:** Ensure it is turned on and that you are retaining logs for long enough (default is often too short for forensic investigation).

**External Sharing Settings:** Set default sharing links to "Specific People" rather than "Anyone with the link."

**Admin Roles:** Use Privileged Identity Management (PIM) to ensure no one has standing "Global Admin" rights.

Step 3: Detecting Illicit Consent Grants

Attackers don't need your password if you give their app permission to read your mail.

**Review App Registrations:** regularly audit Enterprise Applications in Entra ID. Look for apps with low usage but high privileges (e.g., `Mail.Read`, `Files.ReadWrite.All`).

**User Consent Settings:** Disable the ability for users to consent to apps. Require admin approval for any app requesting data access.

Step 4: The "Break Glass" Account

**Emergency Access:** Create two "Break Glass" accounts. These should be:

Cloud-only (not synced from on-prem AD).

Excluded from Conditional Access policies (to prevent locking yourself out).

Monitored with the highest priority (any login triggers an alarm).

How Cydenti Helps

Cydenti acts as an independent watchdog for your M365 environment.

**M365 ISPM:** Continuously checking your tenant against CIS Benchmarks and best practices.

**Behavioral Analytics:** Detecting compromised accounts (e.g., an inbox rule created to forward all mail to an external address) faster than native tools.

**Cross-Tenant Visibility:** If you manage multiple M365 tenants, Cydenti gives you a single dashboard for all of them.

Conclusion

Microsoft 365 is a beast, but it can be tamed. By focusing on identity hygiene—disabling legacy protocols, controlling app consents, and enforcing PIM—you make it exponentially harder for attackers to compromise your digital workspace.