Suspicious request for financial information

  1name: "Suspicious request for financial information"
  2description: "Email is from a suspicious sender and contains a request for financial information, such as AR reports."
  3type: "rule"
  4severity: "high"
  5source: |
  6  type.inbound
  7  and length(attachments) <= 1
  8  and length(recipients.to) <= 2
  9  // suspicious sender
 10  and (
 11    (
 12      length(headers.reply_to) > 0
 13      and all(headers.reply_to,
 14              .email.domain.root_domain != sender.email.domain.root_domain
 15              and .email.domain.root_domain not in $org_domains
 16      )
 17    )
 18    or sender.email.domain.root_domain in $free_email_providers
 19    or profile.by_sender().days_known < 3
 20  )
 21  // specific financial language
 22  and (
 23    regex.icontains(subject.subject,
 24                    '\b(Aged|Age?ing) (Payables|Receivables|Report)',
 25                    'reconcill?iation (report|statement).*(issued (settlement|advice)s?)|billing records?'
 26    )
 27    or (
 28      regex.icontains(body.current_thread.text,
 29                      '\b(Aged|Age?ing) (Payables|Receivables|Report)',
 30                      '(updated|recent) (\bAR\b|\b\AP\b|\bAR\b \& \bAP\b|accounts?) (Payables|Receivables|Reports)',
 31                      '(shared?|send|forward|provide).*remittance (advice|receipts?|statements?)'
 32      )
 33      or strings.icontains(body.current_thread.text,
 34                           "copy of a current statement"
 35      )
 36      or (
 37        strings.icontains(body.current_thread.text, "please send all past due")
 38        and strings.icontains(body.current_thread.text, "current invoices")
 39      )
 40    )
 41    // suspicious link display text
 42    or (
 43      any(body.links,
 44          regex.icontains(.display_text,
 45                          '(Payment|Remittance|Settlement|Transfer) ?Batch',
 46          )
 47      )
 48    )
 49    // suspicious sender display name
 50    or (
 51      regex.icontains(sender.display_name,
 52                      'Accounts? (?:Payable (?:Dep(\.|t\.?|artment)|e?Receipt)|(Co[[:punct:]]?ordinator|Admin|Manager|Payee))'
 53      )
 54      // sender email listed as a recipient or recipients undisclosed/null
 55      and (
 56        (
 57          sender.email.email in map(recipients.to, .email.email)
 58          or (length(recipients.to) == 0 or length(recipients.to) is null)
 59        )
 60        // non-benign nlu intent
 61        or any(ml.nlu_classifier(body.current_thread.text).intents,
 62               .name != "benign"
 63        )
 64      )
 65    )
 66    or (
 67      any(ml.nlu_classifier(body.current_thread.text).intents,
 68          .name == "cred_theft" and .confidence == "high"
 69      )
 70      and any(ml.nlu_classifier(body.current_thread.text).entities,
 71              .name == "financial" and .text =~ "remittance"
 72      )
 73    )
 74  )
 75  // negate resume related/job inquiry outreach
 76  and not (
 77    any(ml.nlu_classifier(body.current_thread.text).topics,
 78        .name == "Professional and Career Development" and .confidence == "high"
 79    )
 80    and any(ml.nlu_classifier(body.current_thread.text).intents,
 81            .name == "benign" and .confidence != "low"
 82    )
 83  )
 84  and (
 85    (
 86      sender.email.domain.root_domain in $high_trust_sender_root_domains
 87      and not headers.auth_summary.dmarc.pass
 88    )
 89    or sender.email.domain.root_domain not in $high_trust_sender_root_domains
 90  )
 91  and not profile.by_sender().any_messages_benign  
 92
 93attack_types:
 94  - "BEC/Fraud"
 95tactics_and_techniques:
 96  - "Free email provider"
 97  - "Impersonation: Employee"
 98  - "Impersonation: VIP"
 99  - "Social engineering"
100detection_methods:
101  - "Content analysis"
102  - "Header analysis"
103  - "Sender analysis"
104id: "4ebdaa4d-4db2-56c6-9a6c-220ad49b7681"