AWS Route 53 Security: DNS Protection and Monitoring

Part of the Cybersecurity Skills Guide — This article is one deep-dive in our complete guide series.

By HADESS Team | February 28, 2026 | Updated: February 28, 2026 | 5 min read

DNS is infrastructure you tend to forget about until it breaks or gets hijacked. Route 53 handles DNS resolution, domain registration, and health checks for your AWS workloads. Securing it means preventing domain takeovers, enabling DNSSEC, controlling DNS resolution behavior, and monitoring query patterns for signs of compromise.

DNSSEC Signing

DNSSEC adds cryptographic signatures to DNS responses, preventing attackers from spoofing DNS records. Without it, a man-in-the-middle can return fake DNS responses and redirect your users to malicious servers.

Route 53 supports DNSSEC signing for public hosted zones. Enable it through the console or API, and Route 53 manages the Zone Signing Key (ZSK) automatically. You manage the Key Signing Key (KSK) through KMS — create a KMS key in us-east-1 (required region for DNSSEC) with the ECC_NIST_P256 key spec.

After enabling DNSSEC, you need to create a Delegation Signer (DS) record with your domain registrar. If Route 53 is your registrar, this is handled through the console. If your registrar is external, export the DS record and add it manually.

Monitor DNSSEC validation with CloudWatch metrics. Route 53 publishes DNSSECInternalFailure and DNSSECKeySigningKeysNeedingAction metrics. Set alarms on these so you do not accidentally break DNS resolution for your domain.

Resolver Rules and DNS Firewall

Route 53 Resolver handles DNS queries for resources in your VPC. By default, VPC resources can resolve any domain on the internet. Route 53 DNS Firewall lets you block or allow specific domains using domain lists.

Create block lists for known malicious domains, C2 infrastructure, and cryptocurrency mining pools. AWS provides managed domain lists for common threats. Add your own lists based on threat intelligence feeds.

Configure DNS Firewall with a fail-open or fail-closed policy. Fail-closed blocks all DNS resolution if the Firewall service is unavailable, which is safer but can cause outages. Choose based on your risk tolerance — most production environments start with fail-open and move to fail-closed after validating stability.

Query Logging

Enable Route 53 Resolver query logging to capture every DNS query from your VPC. Send logs to CloudWatch Logs, S3, or Kinesis Data Firehose. These logs include the queried domain, the source IP within your VPC, and the response.

DNS query logs are a goldmine for security investigations. Look for:

• Queries to newly registered domains (DGA patterns)
• High-frequency queries to a single domain (DNS tunneling)
• Queries to known bad domains (correlate with threat intel)
• Unexpected internal DNS resolution patterns

Domain Takeover Prevention

Dangling DNS records pointing to decommissioned resources (deprovisioned S3 buckets, deleted Elastic Beanstalk environments, released Elastic IPs) create subdomain takeover opportunities. An attacker claims the abandoned resource and serves content on your subdomain.

Audit your hosted zones regularly. Remove CNAME records pointing to resources that no longer exist. Use AWS Config rules to detect dangling DNS entries. Before decommissioning a service, delete its DNS records first.

Enable transfer lock on your domains to prevent unauthorized domain transfers. Use a strong email address for the registrant contact that you monitor and protect with MFA.

Next Steps

• Review network and DNS security topics in the skills library
• Benchmark your skills with the assessment tool
• Plan your network security career path with the coaching tool

Related Guides in This Series

• Active Directory Security: Attack Paths and Hardening — HADESS | 2026
• AWS ALB Security: TLS, Authentication, and Access Controls — HADESS | 2026
• AWS CloudTrail: Log Analysis and Security Monitoring — HADESS | 2026

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