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Is Your Exchange Online Scripting at Risk?
Important Update: Exchange Online PowerShell Security Changes
Microsoft has officially deprecated the -Credential parameter in Exchange Online PowerShell as of February 12, 2026. This critical change impacts how administrators and automation scripts authenticate with Exchange Online. If your current scripts rely on passing a username and password directly via this parameter, they will stop functioning in new module versions released after June 2026.
This shift is not arbitrary; it is a necessary step to fortify security. The -Credential parameter relies on a legacy authentication method known as “Resource Owner Password Credentials” (ROPC). ROPC is inherently insecure because it transmits credentials simply as a username and password, making it incompatible with modern security standards like Multi-Factor Authentication (MFA) and Conditional Access policies. To protect your environment, Microsoft is phasing out this method in favor of more secure, token-based authentication.
Why the -Credential Parameter is Going Away
The deprecation is driven by Microsoft’s broader initiative to enforce Zero Trust security principles.
- Incompatibility with MFA: ROPC cannot support Multi-Factor Authentication. As MFA becomes mandatory across Microsoft cloud services, any method that bypasses it creates a security vulnerability.
- Underlying Library Deprecation: The Microsoft Authentication Library (MSAL), which handles the actual authentication “handshake” for Microsoft services, deprecated ROPC support starting with version 4.74.0.
- Security Compliance: Using -Credential bypasses Conditional Access policies, meaning it ignores rules about where and how a user can log in (e.g., blocking logins from risky IP addresses).
Support for this parameter will be completely removed from all new Exchange Online PowerShell module versions released after June 2026. While existing scripts may continue to work on older module versions temporarily, this is a security risk and is not a sustainable long-term strategy.
Recommended Actions for Administrators
You must audit your current scripts and transition to modern authentication methods immediately. Microsoft recommends specific alternatives based on how your scripts are used.
Next Steps to Future-Proof Your Environment
Don’t wait until the June 2026 deadline.
- Audit Scripts: Scan your repository for Connect-ExchangeOnline commands that use the -Credential parameter.
- Test Modern Auth: Update a pilot script to use App-Only authentication or Managed Identity.
- Update Modules: Ensure you are testing with the latest Exchange Online Management module to verify compatibility with these changes.
By proactively updating your authentication methods, you ensure your automation remains uninterrupted and your organization stays secure against identity-based attacks.