Open redirect: api.spently.com

name: "Open redirect: api.spently.com"
description: |
  Message contains use of the api.spently.com redirect. This has been exploited in the wild.
type: "rule"
severity: "medium"
source: |
  type.inbound
  // there are less than 10 unique links for api.spently.com within the body.links
  and length(distinct(filter(body.links,
                             .href_url.domain.domain == "api.spently.com"
                      ),
                      .href_url.url
             )
  ) < 10
  and any(body.links,
          .href_url.domain.domain == "api.spently.com"
          and strings.istarts_with(.href_url.path, '/api/spently/click')
          and strings.icontains(.href_url.query_params, 'url=')
          and strings.icontains(.href_url.query_params, 'type=')
          and not regex.icontains(.href_url.query_params,
                                  'url=(?:https?(?:%3a|:))?(?:%2f|\/){2}[^&]*spently\.com(?:\&|\/|$|%2f)'
          )
  )
  and not sender.email.domain.root_domain == "spently.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: "69740e97-265f-515b-b5ae-80ec234f07ac"