Open redirect: amaterasu-for-website-5.com

name: "Open redirect: amaterasu-for-website-5.com"
description: |
  Detects messages containing amaterasu-for-website-5.com redirect links that use the url
  parameter to redirect users to malicious sites. This has been observed in phishing campaigns.
type: "rule"
severity: "medium"
source: |
  type.inbound
  and any(body.links,
          // Look for website-5 URLs
          .href_url.domain.domain == "api.amaterasu-for-website-5.com"
          and strings.icontains(.href_url.query_params, 'url=')
          // Make sure it's not redirecting back to website-5.com domains
          and not regex.icontains(.href_url.query_params,
                                  'url=(?:https?(?:%3a|:))?(?:%2f|\/){2}[^&]*website-5\.com(?:\&|\/|$|%2f)'
          )
  )
  // Exclude legitimate website-5 domains as senders
  and not sender.email.domain.root_domain == "website-5.com"
  and not sender.email.domain.root_domain == "amaterasu-for-website-5.com"
  
  // negate highly trusted sender domains unless they fail DMARC authentication
  and (
    (
      sender.email.domain.root_domain in $high_trust_sender_root_domains
      and not headers.auth_summary.dmarc.pass
    )
    or sender.email.domain.root_domain not in $high_trust_sender_root_domains
  )
attack_types:
  - "Credential Phishing"
  - "Malware/Ransomware"
tactics_and_techniques:
  - "Open redirect"
detection_methods:
  - "Sender analysis"
  - "URL analysis"
id: "d31f7cb8-1b75-53ef-b466-7d677392660b"