Implement B2B guest access controls for partner access (Global Secure Access)
Implementation Effort: Medium
User Impact: Medium
Overview
In a Zero Trust network model, external partner access should be segmented and enforced per application and per identity, rather than granting broad network connectivity (for example, traditional VPN-based access). Microsoft Entra Global Secure Access (GSA) supports B2B guest access patterns that allow partners, vendors, and contractors to access only the resources they need while you enforce your organization’s security policies.
Key Zero Trust outcomes for B2B/guest access:
- Identity-driven segmentation: Treat guest access as a distinct segment boundary. Apply policy based on user identity type (guest/external), context, and risk—independent of network location.
- Least privilege, per-app access: Grant guests access only to explicitly approved applications (not entire networks/subnets).
- Conditional Access enforcement: Require MFA and apply risk-, location-, and context-based controls to guest access.
- Cross-tenant trust alignment: Where appropriate, use cross-tenant access settings to trust partner MFA/device claims instead of duplicating controls, while still enforcing your own policies.
- BYOD-ready controls: Support partner devices while limiting access/traffic strictly to assigned applications and monitoring activity.
- Visibility and governance: Monitor guest sign-ins and access activity, and periodically review guest access to ensure it remains appropriate.
Implementation steps:
- Configure Entra B2B collaboration/guest settings and define onboarding/offboarding governance (access reviews, expiration where applicable).
- Configure cross-tenant access settings for partner organizations (inbound trust for MFA/device claims if required).
- Publish partner-accessible apps via Microsoft Entra Private Access and scope access to only the required applications.
- Create Conditional Access policies targeting guest/external users accessing these apps (for example: require MFA, restrict by location/risk, enforce session controls as needed).