Immutable backup storage mounted read write unexpectedly

Scenario

Storage expected to be immutable appears writable from an admin or service account.

Confirm the platform immutability mode and whether the mount path bypasses the intended control.
Review privileges on the backup appliance, repository, and underlying storage.
Test immutability with a controlled write attempt during a maintenance window.
Treat any writable path to immutable storage as a high-priority security defect.

Document what changed, what confirmed the fix, and whether the issue points to a broader standards gap worth addressing for the client.

Subjects