In today's rapidly evolving cybersecurity landscape, organizations using Microsoft 365 need robust tools to identify and mitigate potential security risks. Enter ScubaGear, an open-source PowerShell-based security auditing tool developed by the Cybersecurity and Infrastructure Security Agency (CISA) that helps IT professionals uncover hidden vulnerabilities in their Microsoft 365 environments.

What Is ScubaGear?

ScubaGear is a free, lightweight PowerShell module designed to scan Microsoft 365 tenants for misconfigurations, compliance gaps, and security weaknesses. Unlike commercial alternatives, ScubaGear provides transparent, customizable security assessments without licensing costs. It evaluates key Microsoft 365 services, including:

  • Exchange Online (mail flow rules, admin permissions)
  • SharePoint & OneDrive (external sharing settings)
  • Azure Active Directory (conditional access policies)
  • Teams (guest access controls)

Why Use ScubaGear for Microsoft 365 Security?

1. Open-Source Transparency

Being open-source, ScubaGear allows security teams to review and modify the code, ensuring no hidden backdoors or data collection. This transparency builds trust, especially for government and regulated industries.

2. CISA-Backed Reliability

Developed by CISA, ScubaGear aligns with federal security best practices, making it a credible choice for enterprises seeking compliance with frameworks like NIST or CIS benchmarks.

3. PowerShell Flexibility

Since it runs on PowerShell, ScubaGear integrates seamlessly with existing automation workflows. Administrators can schedule regular scans or customize checks based on organizational policies.

4. Comprehensive Risk Reporting

ScubaGear generates detailed HTML reports highlighting:

  • Overprivileged admin accounts
  • Insecure authentication methods (e.g., legacy protocols)
  • Data leakage risks from external sharing
  • Missing multi-factor authentication (MFA) enforcement

How to Get Started with ScubaGear

Prerequisites

  • PowerShell 5.1 or later
  • Microsoft 365 global admin or security admin permissions
  • Network access to Microsoft 365 endpoints

Installation Steps

  1. Download the Module: Install via PowerShell Gallery:
    powershell Install-Module -Name ScubaGear -Force
  2. Run a Baseline Scan: Execute a basic configuration check:
    powershell Invoke-SCuBA -OutPath .\ScubaReports
  3. Review Findings: Analyze the generated HTML report for actionable insights.

Key Features of ScubaGear

1. Tenant-Wide Security Posture Assessment

ScubaGear evaluates settings across all major Microsoft 365 workloads, providing a unified view of potential risks.

2. Customizable Scans

Administrators can exclude specific checks or focus on high-priority areas like conditional access or mailbox auditing.

3. Offline Mode Support

For air-gapped environments, ScubaGear can export raw data for offline analysis.

4. Community-Driven Updates

As an open-source project, ScubaGear benefits from contributions by security researchers worldwide.

Limitations and Considerations

  • No Real-Time Monitoring: ScubaGear provides point-in-time assessments, not continuous monitoring.
  • Requires Admin Rights: Running scans necessitates elevated privileges, which may not be feasible in all environments.
  • PowerShell Dependency: Organizations restricting PowerShell usage may face deployment hurdles.

ScubaGear vs. Commercial Alternatives

While tools like Microsoft Secure Score or Tenable.io offer similar functionality, ScubaGear stands out due to:

  • Zero Cost: No subscription fees or feature limitations.
  • Custom Scripting: PowerShell integration allows tailored security checks.
  • Government Trust: CISA’s endorsement adds credibility for public-sector adopters.

Best Practices for Using ScubaGear

  1. Run Regular Scans: Schedule monthly audits to track improvements.
  2. Combine with Microsoft Secure Score: Use both tools for a layered security approach.
  3. Address Critical Findings First: Prioritize high-risk issues like unused admin accounts.
  4. Contribute Back to the Project: Report bugs or suggest enhancements via GitHub.

The Future of ScubaGear

CISA continues to enhance ScubaGear with new checks for emerging Microsoft 365 features. Upcoming updates may include:

  • Copilot for Microsoft 365 Security Reviews
  • Enhanced Entra ID (Azure AD) Assessments
  • Deeper Teams Security Analysis

Conclusion

ScubaGear is a powerful, no-cost solution for organizations serious about Microsoft 365 security. By leveraging open-source transparency and CISA’s expertise, it empowers IT teams to proactively harden their cloud environments. Whether you’re a small business or a federal agency, integrating ScubaGear into your security toolkit can significantly reduce exposure to cyber threats.

For more details, visit ScubaGear’s GitHub repository.