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ACM certificate is imported or has Certificate Transparency logging enabled

acm_certificates_transparency_logs_enabled
Service: acmSeverity: medium
OfficialBuilt-inVerified
Categories:logging
Resource Type:AwsCertificateManagerCertificate

ACM-issued certificates are checked for Certificate Transparency (CT) logging being enabled. Certificates with type IMPORTED are excluded from evaluation.

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Risk

Disabling CT logging reduces visibility into misissued or rogue certificates, weakening confidentiality and integrity. Attackers can impersonate sites or run TLS man-in-the-middle without timely detection. Unlogged public certs may be distrusted by browsers, impacting availability and user trust.

Run this check with Prowler

Run in Prowler Cloud
Run
prowler aws --checks acm_certificates_transparency_logs_enabled

Recommendation

Enable CT logging on all ACM-issued public certificates to maintain transparency and rapid revocation.

Monitor CT logs for your domains and alert on unexpected issuances. For sensitive internal names, favor private PKI or non-public hostnames instead of disabling CT, and apply defense in depth with short certificate lifetimes.

Remediation

CLI

aws acm update-certificate-options --certificate-arn <CERTIFICATE_ARN> --options CertificateTransparencyLoggingPreference=ENABLED

Terraform

# Enable Certificate Transparency logging on an ACM certificate
resource "aws_acm_certificate" "<example_resource_name>" {
  domain_name = "<example_domain_name>"
  options {
    certificate_transparency_logging_preference = "ENABLED"  # Critical: turns on CT logging to pass the check
  }
}

NativeIaC

# CloudFormation: Enable Certificate Transparency logging on an ACM certificate
Resources:
  <example_resource_name>:
    Type: AWS::CertificateManager::Certificate
    Properties:
      DomainName: <example_domain_name>
      CertificateTransparencyLoggingPreference: ENABLED  # Critical: turns on CT logging to pass the check

Other

1Open the AWS Certificate Manager (ACM) console
2Select the certificate with transparency logging disabled
3Click Actions > Edit transparency logging
4Choose Enable transparency logging
5Click Save

Check Code

from prowler.lib.check.models import Check, Check_Report_AWS
from prowler.providers.aws.services.acm.acm_client import acm_client


class acm_certificates_transparency_logs_enabled(Check):
    def execute(self):
        findings = []
        for certificate in acm_client.certificates.values():
            if certificate.in_use or acm_client.provider.scan_unused_services:
                report = Check_Report_AWS(
                    metadata=self.metadata(), resource=certificate
                )
                if certificate.type == "IMPORTED":
                    report.status = "PASS"
                    report.status_extended = f"ACM Certificate {certificate.id} for {certificate.name} is imported."
                else:
                    if not certificate.transparency_logging:
                        report.status = "FAIL"
                        report.status_extended = f"ACM Certificate {certificate.id} for {certificate.name} has Certificate Transparency logging disabled."
                    else:
                        report.status = "PASS"
                        report.status_extended = f"ACM Certificate {certificate.id} for {certificate.name} has Certificate Transparency logging enabled."
                findings.append(report)
        return findings

References