Vulnerable Default SSL Certificate

• Query id: 3a1e94df-6847-4c0e-a3b6-6c6af4e128ef
• Query name: Vulnerable Default SSL Certificate
• Platform: Terraform
• Severity: High
• Category: Insecure Defaults
• URL: Github

Description

CloudFront web distributions should use custom (and not default) SSL certificates. Custom SSL certificates allow only defined users to access content by using an alternate domain name instead of the default one.
Documentation

Code samples

Code samples with security vulnerabilities

Positive test num. 1 - tf file

resource "aws_s3_bucket" "positive1" {
  # configs
}

resource "aws_cloudfront_distribution" "positive2" {
  origin {
    domain_name = aws_s3_bucket.positive1.bucket_regional_domain_name
    origin_id   = local.s3_origin_id

    s3_origin_config {
      origin_access_identity = "origin-access-identity/cloudfront/ABCDEFG1234567"
    }
  }

  enabled             = true
  is_ipv6_enabled     = true
  comment             = "Some comment"
  default_root_object = "index.html"

  default_cache_behavior {
    allowed_methods  = ["DELETE", "GET", "HEAD", "OPTIONS", "PATCH", "POST", "PUT"]
    cached_methods   = ["GET", "HEAD"]
    target_origin_id = local.s3_origin_id

    forwarded_values {
      query_string = false

      cookies {
        forward = "none"
      }
    }

    viewer_protocol_policy = "allow-all"
    min_ttl                = 0
    default_ttl            = 3600
    max_ttl                = 86400
  }

  restrictions {
    geo_restriction {
      restriction_type = "whitelist"
      locations        = ["US", "CA", "GB", "DE"]
    }
  }
}

resource "aws_cloudfront_distribution" "positive3" {
  origin {
    domain_name = aws_s3_bucket.positive1.bucket_regional_domain_name
    origin_id   = local.s3_origin_id

    s3_origin_config {
      origin_access_identity = "origin-access-identity/cloudfront/ABCDEFG1234567"
    }
  }

  enabled             = true
  is_ipv6_enabled     = true
  comment             = "Some comment"
  default_root_object = "index.html"

  default_cache_behavior {
    allowed_methods  = ["DELETE", "GET", "HEAD", "OPTIONS", "PATCH", "POST", "PUT"]
    cached_methods   = ["GET", "HEAD"]
    target_origin_id = local.s3_origin_id

    forwarded_values {
      query_string = false

      cookies {
        forward = "none"
      }
    }

    viewer_protocol_policy = "allow-all"
    min_ttl                = 0
    default_ttl            = 3600
    max_ttl                = 86400
  }

  restrictions {
    geo_restriction {
      restriction_type = "whitelist"
      locations        = ["US", "CA", "GB", "DE"]
    }
  }

  viewer_certificate {
    cloudfront_default_certificate = true
  }
}

resource "aws_cloudfront_distribution" "positive4" {
  origin {
    domain_name = aws_s3_bucket.positive1.bucket_regional_domain_name
    origin_id   = local.s3_origin_id

    s3_origin_config {
      origin_access_identity = "origin-access-identity/cloudfront/ABCDEFG1234567"
    }
  }

  enabled             = true
  is_ipv6_enabled     = true
  comment             = "Some comment"
  default_root_object = "index.html"

  default_cache_behavior {
    allowed_methods  = ["DELETE", "GET", "HEAD", "OPTIONS", "PATCH", "POST", "PUT"]
    cached_methods   = ["GET", "HEAD"]
    target_origin_id = local.s3_origin_id

    forwarded_values {
      query_string = false

      cookies {
        forward = "none"
      }
    }

    viewer_protocol_policy = "allow-all"
    min_ttl                = 0
    default_ttl            = 3600
    max_ttl                = 86400
  }

  restrictions {
    geo_restriction {
      restriction_type = "whitelist"
      locations        = ["US", "CA", "GB", "DE"]
    }
  }

  viewer_certificate {
    acm_certificate_arn = aws_acm_certificate_validation.cert.certificate_arn
  }
}

Code samples without security vulnerabilities

Negative test num. 1 - tf file

resource "aws_s3_bucket" "negative1" {
  # configs
}

resource "aws_cloudfront_distribution" "negative2" {
  origin {
    domain_name = aws_s3_bucket.negative1.bucket_regional_domain_name
    origin_id   = local.s3_origin_id

    s3_origin_config {
      origin_access_identity = "origin-access-identity/cloudfront/ABCDEFG1234567"
    }
  }

  enabled             = true
  is_ipv6_enabled     = true
  comment             = "Some comment"
  default_root_object = "index.html"

  default_cache_behavior {
    allowed_methods  = ["DELETE", "GET", "HEAD", "OPTIONS", "PATCH", "POST", "PUT"]
    cached_methods   = ["GET", "HEAD"]
    target_origin_id = local.s3_origin_id

    forwarded_values {
      query_string = false

      cookies {
        forward = "none"
      }
    }

    viewer_protocol_policy = "allow-all"
    min_ttl                = 0
    default_ttl            = 3600
    max_ttl                = 86400
  }

  restrictions {
    geo_restriction {
      restriction_type = "whitelist"
      locations        = ["US", "CA", "GB", "DE"]
    }
  }

  viewer_certificate {
    acm_certificate_arn      = aws_acm_certificate_validation.cert.certificate_arn
    ssl_support_method       = "sni-only"
    minimum_protocol_version = "TLSv1.2_2018"
  }
}