Microsoft AzureOverview
[NOTE: As of August 1, 2023, customers with an existing subscription to Defender for DNS can continue to use the service, but new subscribers will receive alerts about suspicious DNS activity as part of Defender for Servers P2.]
Microsoft Defender for DNS scans all network traffic exiting from within a subscription.
Rationale
DNS lookups within a subscription are scanned and compared to a dynamic list of websites with potential security threats. These threats could result from a security breach within your services, so scanning for them could prevent a potential security threat from being introduced.
Impact
Enabling Microsoft Defender for DNS requires enabling Microsoft Defender for your subscription. Both will incur additional charges, with Defender for DNS being a small amount per million queries.
Remediation guidance
From Azure Console
- Open Microsoft Defender for Cloud | Environment settings
- Select a subscription
- Under
Settings, selectDefender plans - For
DNS, selectOnforStatus - Select Save
Using Azure Command Line Interface
az security pricing create -n 'DNS' --tier 'Standard'
Using Azure PowerShell
Set-AzSecurityPricing -Name 'DNS' -PricingTier 'Standard'
Default Value
By default, Microsoft Defender for DNS is not enabled.
References
- https://azure.microsoft.com/en-us/pricing/details/defender-for-cloud/
- https://learn.microsoft.com/en-us/security/benchmark/azure/baselines/dns-security-baseline
- https://learn.microsoft.com/en-us/azure/defender-for-cloud/defender-for-dns-alerts
- https://learn.microsoft.com/en-us/azure/defender-for-cloud/enable-enhanced-security
- https://learn.microsoft.com/en-us/azure/defender-for-cloud/alerts-overview
- https://learn.microsoft.com/en-us/security/benchmark/azure/security-controls-v3-network-security#ns-10-ensure-domain-name-system-dns-security
- https://learn.microsoft.com/en-us/security/benchmark/azure/security-controls-v3-logging-threat-detection#lt-1-enable-threat-detection-capabilities
Service-wide remediation
Recommended when many resources are affected: fix the platform baseline first so new resources inherit the secure setting, then remediate the existing flagged resources in batches.
Azure
Use management group or subscription Azure Policy assignments, remediation tasks where supported, landing-zone standards, and IaC modules so drift is prevented at scale.
Operational rollout
- Fix the baseline first at the account, subscription, project, cluster, or tenant scope that owns this control.
- Remediate the currently affected resources in batches, starting with internet-exposed and production assets.
- Re-scan and track approved exceptions with an owner and expiry date.
Query logic
These are the stored checks tied to this control.
Azure Subscriptions without Microsoft Defender for DNS
Connectors
Covered asset types
Expected check: eq []
{
connectors(
where: { pricing_SOME: { name: "Dns", pricingTier: "Free" } }
) {
...AssetFragment
}
}
