Brand impersonation: Microsoft quarantine release notification in body

name: "Brand impersonation: Microsoft quarantine release notification in body"
description: "Message containing suspicious quarantine release language in the body, and a Microsoft logo attachment but did not come from Microsoft."
type: "rule"
severity: "high"
source: |
  type.inbound
  and length(filter(attachments, .file_type not in $file_types_images)) == 0
  and any(attachments,
          any(file.explode(.),
              (
                // attachment is most likely only a logo 
                (
                  length(.scan.ocr.raw) < 15 or .scan.ocr.raw is null
                )
                and any(ml.logo_detect(..).brands,
                        strings.starts_with(.name, "Microsoft")
                )
              )
          )
          and (
            3 of (
              strings.ilike(body.current_thread.text, "*review*"),
              strings.ilike(body.current_thread.text, "*release*"),
              strings.ilike(body.current_thread.text, "*quarantine*"),
              strings.ilike(body.current_thread.text, "*messages*"),
              strings.ilike(body.current_thread.text, "*blocked*"),
              strings.ilike(body.current_thread.text, "*notification*"),
              strings.ilike(body.current_thread.text, "*kindly*")
            )
          )
  )
  and sender.email.domain.root_domain not in (
    "bing.com",
    "microsoft.com",
    "microsoftonline.com",
    "microsoftsupport.com",
    "microsoft365.com",
    "office.com",
    "office365.com",
    "onedrive.com",
    "sharepointonline.com",
    "yammer.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
  )
  and not profile.by_sender().solicited
  and not profile.by_sender().any_messages_benign
  
attack_types:
  - "Credential Phishing"
tactics_and_techniques:
  - "Impersonation: Brand"
  - "Social engineering"
detection_methods:
  - "Computer Vision"
  - "Content analysis"
  - "File analysis"
  - "Sender analysis"
id: "6d19527c-7ab9-5f0d-8c35-718dd30b704f"