CRITICAL SEVERITYCLOUDCVSS 8.6Requires Account VerificationID: aws-cloudfront

AWS CloudFront Dangling DNS & Takeover Fingerprint

A CNAME references an unallocated or deleted CloudFront distribution. If an attacker knows the target, they can attempt to bind the custom domain to a newly provisioned CloudFront distribution.

DNS CNAME Delegation Rules

Target CNAME Delegation

*.cloudfront.net

DNS Resolution Indicator

CNAME resolves to *.cloudfront.net. Edge node returns 403 or 'The request could not be satisfied'.

Expected HTTP Status Code

403 Forbidden / 404

Authoritative Response Token

Vulnerable Body Indicator String

“NoSuchDistribution”

CLI Verification Command

curl -sI https://subdomain.example.com | grep -E '(NoSuchDistribution|CloudFront)'

When SubdomainWatch scanner identifies this response on an unresolved CNAME target, an automated alert is triggered within 800ms.

Remediation Guide & Defensive Action Plan

Immediate Action Required: Remove the dangling CNAME or ensure the CloudFront distribution is active with an attached ACM SSL certificate covering the custom domain.

Defensive Verification Checklist:

Audit authoritative DNS zone records for any CNAME pointing to *.cloudfront.net.
Verify whether the target resource or bucket still exists under your organization's cloud tenant.
If decommissioned, delete the DNS record immediately to close the public exposure window.
Deploy a pre-merge IaC security gate (such as SubdomainWatch Takeover Guard) to intercept dangling records before pull requests merge.

Terraform Remediation Example

resource "aws_cloudfront_distribution" "cdn" {
  aliases = ["subdomain.example.com"]
  viewer_certificate {
    acm_certificate_arn = aws_acm_certificate.cert.arn
  }
}

Open Dedicated AWS CloudFront Terraform Solution Guide →

ATTACK SURFACE DETECTION COMPARISON

Why Static DNS Scanners Miss AWS CloudFront Takeovers

Passive DNS repositories like SecurityTrails and heavy scanners like Detectify record domain records retrospectively or trigger alert fatigue. SubdomainWatch conducts active recursive CNAME testing with zero false positives.

SubdomainWatch vs SecurityTrails →SubdomainWatch vs Detectify →All 5 Competitor Benchmarks →

AWS CloudFront Takeover FAQs

AWS requires custom domains on CloudFront to possess a valid ACM SSL certificate in us-east-1 verifying ownership. However, if DNS validation records are also dangling, an adversary can issue the certificate and claim the distribution.

This CloudFront edge error indicates that no CloudFront distribution currently configured recognizes the incoming Host header as an alternate domain name (CNAME alias).

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