* Goal: Apply least privilege for Cloud Shell to run diagnostics (ping, traceroute, nc) within a VCN.
* Option A: Read permission on all virtual-network-family resources is too broad, granting unnecessary access beyond diagnostics-violates least privilege.
* Option B: Instance Principals use temporary credentials tied to the Cloud Shell instance, enhancing security. A dynamic group with "read" and "use" permissions on NSGs and VNICs allows inspecting configurations and running diagnostics (e.g., via VNICs), meeting the exact need-correct.
* Option C: Inspect permission only provides metadata access, insufficient for running diagnostics (e.g., no "use" for traffic)-incorrect.
* Option D: Use permission on virtual-network-family at tenancy level is overly permissive, granting access to all network resources-violates least privilege.
* Conclusion: Option B is the most restrictive and secure, aligning with least privilege.
Oracle states:
* "Instance Principals allow services like Cloud Shell to authenticate without static credentials. Policies with 'read' and 'use' on specific resources (e.g., network-security-groups, vnics) enable diagnostics while adhering to least privilege."This supports Option B. Reference:Instance Principals - Oracle Help Center(docs.oracle.com/en-us/iaas/Content/Identity/Tasks/instanceprincipals.htm).