[ DNS & domains ]
DNS API credentials: restrict the zones and actions they can reach
Review DNS automation identities by resource scope, permitted actions, inherited access and lifecycle without collecting or testing secrets.
By the EmailAuth research team · 8 min read
[ Key points ]
- A configured domain list is not an enforced credential boundary.
- Restrict both resources and actions using the provider’s actual authorization model.
- Keep secrets out of evidence and validate safe record-set update behavior.
[ Takeaway ]
Approve an accountable automation identity whose effective permissions match its job, and review its consumers, update semantics and retirement plan.
[ By role ]
What this means for you
Choose your role for practical next steps.
IT / Mail Admin
Map the API job precisely
The writer must know which complete record sets its operation can replace.
Next steps
- List required reads and mutations by zone and record type.
- Preserve current records and use supported version checks.
- Document every known automation consumer.
CISO / SecOps
Constrain the workload identity
Authentication alone does not demonstrate least privilege.
Next steps
- Review direct and inherited permissions.
- Evaluate managed identity support without creating credentials.
- Keep secret values out of tickets and logs.
Founder / Non-technical
Own the automation lifecycle
A shared credential can outlive the job that justified it.
Next steps
- Assign a service owner and review date.
- Separate production and unrelated job requirements.
- Require consumer migration and recovery planning before retirement.
[ FAQs ]
Frequently asked questions
Does listing one zone in the script restrict the credential?
No. Application configuration is not the same as enforced authorization. Review the principal’s actual resource scope and actions.
Is a DNS-only role always narrow enough?
No. It can still cover more zones or operations than the workload needs. Evaluate resource scope and action permissions separately.
What can Azure TXT write permission do?
The operation catalogue describes creating or updating a TXT record set with supplied records replacing current records. It is not necessarily an append-only capability.
Does a managed identity automatically get DNS access?
No. It provides an authentication identity for supported workloads; the relevant authorization still needs to be designed and granted through an approved process.
Are user-assigned and system-assigned identities retired the same way?
No. System-assigned identity lifecycle is tied to its resource, while a user-assigned identity is separately managed and may serve multiple resources.
Should a review worksheet contain the API secret?
No. Use non-secret identity and approved storage references. This proposed review neither needs nor requests credential values.
Can I test scope by trying an unapproved production write?
No. This guide proposes read-only assessment first. Any mutation test requires its own authorized resource and method; no live permission tests are reported.
Does least privilege prevent stale record overwrites?
Not by itself. The client still needs safe update behavior. The cited Azure REST operation supports If-Match with the last-seen ETag to avoid replacing concurrent changes.
[ Sources ]
Sources
- Microsoft: Protecting DNS zones and records
Sections The DNS Zone Contributor role · Zone level Azure RBAC · Record set level Azure RBAC · Custom roles · Resource locks
- Microsoft: Understand scope for Azure RBAC
Sections Scope levels · Scope format
- Microsoft: Azure permissions for Networking
Sections Microsoft.Network/dnsZones · Microsoft.Network/dnszones/TXT/read · Microsoft.Network/dnszones/TXT/write · Microsoft.Network/dnszones/CNAME/write
- Microsoft: DNS Record Sets Create Or Update REST API
Sections Request Header: If-Match · Request Header: If-None-Match · Request Body
- Microsoft: Managed identities for Azure resources overview
Sections What are managed identities? · Types of managed identities · How can I use a managed identity for an Azure resource?
- Microsoft: Securing service principals
Sections Assess service principal security · Move from a user account to a service principal
[ Glossary ]
Glossary
- Principal
- The identity to which authorization is assigned for the workload or user.
- Resource scope
- The boundary of resources to which a role assignment applies.
- Managed identity
- An Azure-supported workload identity that can obtain tokens without developers managing its secret credentials.
- Consumer inventory
- The list of jobs and services relying on an automation identity, used to plan review and retirement.
Enterprise provenance
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