Sublime Security medium experimental mql

Callback phishing via Intuit service abuse

Callback phishing campaigns have been observed abusing Intuit Quickbooks services to send fraudulent invoices with callback phishing contents.

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Detection Logic

type.inbound

// Legitimate Intuit sending infratructure
and (
  sender.email.domain.root_domain in ('intuit.com', 'intuit.co.uk')
  // check for SPF or DMARC passed
  and (headers.auth_summary.spf.pass or headers.auth_summary.dmarc.pass)
)
and (
  // Callback Phishing in body (brand names required)
  (
    length(attachments) == 0

    // brand names are required.
    and regex.icontains(strings.replace_confusables(body.current_thread.text),
                        (
                          "mcafee
| norton
| geek.{0,5}squad
| paypal
| ebay
| symantec
| best buy
| lifelock"
                        )
    )
    and 3 of (
      strings.ilike(body.current_thread.text, '*purchase*'),
      strings.ilike(body.current_thread.text, '*payment*'),
      strings.ilike(body.current_thread.text, '*transaction*'),
      strings.ilike(body.current_thread.text, '*subscription*'),
      strings.ilike(body.current_thread.text, '*antivirus*'),
      strings.ilike(body.current_thread.text, '*order*'),
      strings.ilike(body.current_thread.text, '*support*'),
      strings.ilike(body.current_thread.text, '*help line*'),
      strings.ilike(body.current_thread.text, '*receipt*'),
      strings.ilike(body.current_thread.text, '*invoice*'),
      strings.ilike(body.current_thread.text, '*call*'),
      strings.ilike(body.current_thread.text, '*cancel*'),
      strings.ilike(body.current_thread.text, '*renew*'),
      strings.ilike(body.current_thread.text, '*refund*')
    )
    // phone number regex
    and any([body.current_thread.text, subject.subject],
            regex.icontains(., '\b\+?(\d{1}.)?\(?\d{3}?\)?.\d{3}.?\d{4}\b')
    )
  )
  // Callback Phishing in the "billtoContent"
  or 
  // icontains a phone number
  (
    regex.icontains(strings.replace_confusables(body.html.inner_text),
                    '(?:Sold
| Bill)[\s\xa0]To(?:\:\s+
| \n)[^\n]+\+?(\d{1}.)?\(?\d{3}?\)?.\d{3}.?\d{4}.*\n'
    )
    or regex.icontains(strings.replace_confusables(body.html.inner_text),
                       '(?:Sold
| Bill)[\s\xa0]To(?:\:\s+
| \n)[^\n]+\+\d{1,3}[ilo0-9]{10}.*\n'
    )
    // +12028001238
    or regex.icontains(strings.replace_confusables(body.html.inner_text),
                       '(?:Sold
| Bill)[\s\xa0]To(?:\:\s+
| \n)[^\n]+[ilo0-9]{3}\.[ilo0-9]{3}\.[ilo0-9]{4}.*\n'
    )
    // 202-800-1238
    or regex.icontains(strings.replace_confusables(body.html.inner_text),
                       '(?:Sold
| Bill)[\s\xa0]To(?:\:\s+
| \n)[^\n]+[ilo0-9]{3}-[ilo0-9]{3}-[ilo0-9]{4}.*\n'
    )
    // (202) 800-1238
    or regex.icontains(strings.replace_confusables(body.html.inner_text),
                       '(?:Sold
| Bill)[\s\xa0]To(?:\:\s+
| \n)[^\n]+\([ilo0-9]{3}\)[\s-]+[ilo0-9]{3}[\s-]+[ilo0-9]{4}.*\n'
    )
    // (202)-800-1238
    or regex.icontains(strings.replace_confusables(body.html.inner_text),
                       '(?:Sold
| Bill)[\s\xa0]To(?:\:\s+
| \n)[^\n]+\([ilo0-9]{3}\)-[ilo0-9]{3}-[ilo0-9]{4}.*\n'
    )
    // 202 800 1238
    or regex.icontains(strings.replace_confusables(body.html.inner_text),
                       '(?:Sold
| Bill)[\s\xa0]To(?:\:\s+
| \n)[^\n]+1\s?[ilo0-9]{3} [ilo0-9]{3} [ilo0-9]{4}.*\n'
    ) // 8123456789
    or (
      regex.icontains(strings.replace_confusables(body.html.inner_text),
                      '(?:Sold
| Bill)[\s\xa0]To(?:\:\s+
| \n)[^\n]+8\d{9}.*\n'
      )
      and regex.icontains(strings.replace_confusables(body.html.inner_text),
                          '\+1'
      )
    )
  )
  // all attachments are PDFs with callback phishing indicators Brands Required
  or (
    length(attachments) < 3
    and all(attachments, .file_extension == "pdf")
    // the attachment is a pdf with 1 page, and at least 60 ocr chars
    and any(attachments,
            (
              .file_extension == "pdf"
              and any(file.explode(.), .scan.exiftool.page_count < 3)
              and any(file.explode(.), length(.scan.ocr.raw) > 60)

              // 4 of the following strings are found
              and (
                any(file.explode(.),
                    4 of (
                      strings.icontains(.scan.ocr.raw, "purchase"),
                      strings.icontains(.scan.ocr.raw, "payment"),
                      strings.icontains(.scan.ocr.raw, "transaction"),
                      strings.icontains(.scan.ocr.raw, "subscription"),
                      strings.icontains(.scan.ocr.raw, "antivirus"),
                      strings.icontains(.scan.ocr.raw, "order"),
                      strings.icontains(.scan.ocr.raw, "support"),
                      strings.icontains(.scan.ocr.raw, "help line"),
                      strings.icontains(.scan.ocr.raw, "receipt"),
                      strings.icontains(.scan.ocr.raw, "invoice"),
                      strings.icontains(.scan.ocr.raw, "call"),
                      strings.icontains(.scan.ocr.raw, "helpdesk"),
                      strings.icontains(.scan.ocr.raw, "cancel"),
                      strings.icontains(.scan.ocr.raw, "renew"),
                      strings.icontains(.scan.ocr.raw, "refund"),
                      strings.icontains(.scan.ocr.raw, "amount"),
                      strings.icontains(.scan.ocr.raw, "crypto"),
                      strings.icontains(.scan.ocr.raw, "wallet address"),
                      regex.icontains(.scan.ocr.raw, '\$\d{3}\.\d{2}\b'),
                      regex.icontains(.scan.ocr.raw,
                                      '(\+\d
| 1.(\()?\d{3}(\))?\D\d{3}\D\d{4})'
                      ),
                      regex.icontains(.scan.ocr.raw,
                                      '\+?(\d{1,2})?\s?\(?\d{3}\)?[\s\.\-⋅]{0,5}\d{3}[\s\.\-⋅]{0,5}\d{4}'
                      )
                    )

                    // 1 of the following strings is found, representing common Callback brands
                    and (
                      1 of (
                        strings.icontains(.scan.ocr.raw, "geek squad"),
                        strings.icontains(.scan.ocr.raw, "lifelock"),
                        strings.icontains(.scan.ocr.raw, "best buy"),
                        strings.icontains(.scan.ocr.raw, "mcafee"),
                        strings.icontains(.scan.ocr.raw, "norton"),
                        strings.icontains(.scan.ocr.raw, "ebay"),
                        strings.icontains(.scan.ocr.raw, "paypal"),
                      )
                      // add additional logic for common language for paypal, which is a valid payment method
                      and not regex.icontains(.scan.ocr.raw,
                                              "paypal[^\n]+accepted"
                      )
                      and not regex.icontains(.scan.ocr.raw,
                                              "pay(ment)?.{0,30}(via
| by) paypal"
                      )
                      and not regex.icontains(.scan.ocr.raw,
                                              '\d{2,4} norton'
                      ) // an address, example: 1234 Norton Road
                      and not regex.icontains(.scan.ocr.raw,
                                              'sold on.{0,20}ebay'
                      ) // "cannot be sold on Amazon and EBay", from a legit vendor
                    )
                )
                or any(ml.logo_detect(.).brands,
                       .name in ("PayPal", "Norton", "GeekSquad", "Ebay")
                )
              )
            )
    )
  )
)

//
// This rule makes use of a beta feature and is subject to change without notice
// using the beta feature in custom rules is not suggested until it has been formally released
//
and (
  not beta.profile.by_reply_to().any_messages_benign
  or length(headers.reply_to) == 0
)

Field Validations

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