How Businesses Can Improve Their Microsoft 365 Security Posture

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Why Microsoft 365 Security
is Essential for Businesses

A financial services firm recently suffered a security breach when cybercriminals gained access to an unprotected Microsoft 365 account. Using stolen credentials, the attackers accessed confidential financial records, sent fraudulent emails, and attempted to transfer funds to offshore accounts.

The issue? The company had not implemented multi-factor authentication (MFA), lacked endpoint security, and had misconfigured Microsoft 365 security settings.

Microsoft 365 provides powerful cloud collaboration tools, but default security settings aren’t enough to protect businesses from cyber threats. Organisations must proactively secure their Microsoft 365 environments to prevent data breaches, insider threats, and ransomware attacks.

Top Security Risks in
Microsoft 365 Environments

Microsoft 365 security

1

Weak Authentication & Lack of MFA

Without Multi-Factor Authentication (MFA), stolen credentials can be used to access business-critical data.

Solution:

  • Enforce MFA for all accounts using the Microsoft Authenticator app.
  • Implement passwordless authentication for high-privilege users.
  • Use Microsoft Entra ID (Azure AD) Identity Protection to detect suspicious logins.

2

Phishing & Business Email Compromise (BEC)

Cybercriminals spoof executive emails and trick employees into transferring money or sharing sensitive data.

 Solution:

  • Enable Microsoft Defender for Office 365 to block phishing emails.
  • Use Safe Links & Safe Attachments to prevent malicious file downloads.
  • Implement DMARC, SPF, and DKIM to stop email spoofing.
Microsoft 365 security

Microsoft 365 security

3

Data Leaks & Insider Threats

Employees accidentally share sensitive documents or malicious insiders steal business data.

Solution:

  • Deploy Microsoft Purview Data Loss Prevention (DLP) to block unauthorised data sharing.
  • Monitor file access with Microsoft 365 Audit Logs.
  • Restrict file downloads and sharing using OneDrive and SharePoint security policies.

4

Unpatched Devices & Endpoint Vulnerabilities

Unprotected devices provide an entry point for attackers to spread ransomware and steal business data.

Solution:

  • Use Microsoft Defender for Endpoint to detect and isolate compromised devices.
  • Enable automatic security updates for Windows and Microsoft 365 apps.
  • Require device compliance checks before granting access to company data.
Microsoft 365 security

Best Practices for Strengthening
Microsoft 365 Security

  • Improve Microsoft Secure Score
    Regularly review and implement Microsoft security recommendations to improve tenant security.
  • Implement Conditional Access Policies
    Restrict access based on device health, location, and risk level.
  • Limit Global Admin Privileges
    Reduce the number of global administrators and enable privileged access management.
  • Enable Microsoft Defender for Microsoft 365
    Protect email, identities, and cloud data with AI-powered threat detection.
  • Regularly Audit Security Logs
    Use Microsoft Sentinel to track unusual login activity and potential threats.

How Microsoft 365 Protects
Businesses from Cyber Threats

  • Microsoft Defender for Microsoft 365
    Stops phishing, ransomware, and malware threats in real time.
  • Microsoft Secure Score
    Provides actionable security recommendations for improving protection.
  • Microsoft Entra ID (Azure AD) Conditional Access
    Blocks risky sign-ins and unauthorised access attempts.
  • Microsoft Purview Compliance Centre
    Helps businesses meet security and data protection regulations.

Conclusion: Microsoft 365 Security
Requires Proactive Management

Cybercriminals continuously target Microsoft 365 environments, exploiting weak security settings, stolen credentials, and insider threats. Businesses that fail to implement security best practices risk data breaches, financial losses, and compliance violations.

By improving Microsoft Secure Score, enabling advanced security features, and enforcing Zero Trust policies, businesses can enhance Microsoft 365 security and protect critical business data.

Want to secure your Microsoft 365 environment?

Contact Solid Systems today for expert Microsoft 365 security solutions!

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Microsoft Secure Score