Sublime Security medium experimental mql

Callback phishing via Zelle Service Abuse

Callback phishing campaigns have been observed abusing Zelle services to send fraudulent payment requests with callback phishing contents.

View Source

Detection Logic

type.inbound
and length(attachments) == 0
and sender.email.domain.root_domain in ("zellepay.com")
and (
  // only seeing payment requests abused
  strings.ilike(body.html.display_text, "* requested*")
  // phone number in subject
  // the subject contains the seller's "name", attacks have been seen with the entire callback text in the seller's name
  or (
    regex.icontains(strings.replace_confusables(subject.subject),
                    '.*\+?([ilo0-9]{1}.)?\(?[ilo0-9]{3}?\)?.[ilo0-9]{3}.?[ilo0-9]{4}.*'
    )
    or regex.icontains(strings.replace_confusables(subject.subject),
                       '.*\+[ilo0-9]{1,3}[ilo0-9]{10}.*'
    )
    // +12028001238
    or regex.icontains(strings.replace_confusables(subject.subject),
                       '.*[ilo0-9]{3}\.[ilo0-9]{3}\.[ilo0-9]{4}.*'
    )
    // 202-800-1238
    or regex.icontains(strings.replace_confusables(subject.subject),
                       '.*[ilo0-9]{3}-[ilo0-9]{3}-[ilo0-9]{4}.*'
    )
    // (202) 800-1238
    or regex.icontains(strings.replace_confusables(subject.subject),
                       '.*\([ilo0-9]{3}\)[\s-]+[ilo0-9]{3}[\s-]+[ilo0-9]{4}.*'
    )
    // (202)-800-1238
    or regex.icontains(strings.replace_confusables(subject.subject),
                       '.*\([ilo0-9]{3}\)-[ilo0-9]{3}-[ilo0-9]{4}.*'
    )
    or ( // 8123456789
      regex.icontains(strings.replace_confusables(subject.subject),
                      '.*8[ilo0-9]{9}.*'
      )
      and regex.icontains(strings.replace_confusables(subject.subject),
                          '\+[1li]'
      )
    )
  )
)
and (
  (
    // icontains a phone number within the memo section (wrapped in quotes)
    (
      regex.icontains(strings.replace_confusables(body.current_thread.text),
                      '\".*\+?([ilo0-9]{1}.)?\(?[ilo0-9]{3}?\)?.[ilo0-9]{3}.?[ilo0-9]{4}.*\"'
      )
      or regex.icontains(strings.replace_confusables(body.current_thread.text),
                         '\".*\+[ilo0-9]{1,3}[ilo0-9]{10}.*\"'
      )
      // +12028001238
      or regex.icontains(strings.replace_confusables(body.current_thread.text),
                         '\".*[ilo0-9]{3}\.[ilo0-9]{3}\.[ilo0-9]{4}.*\"'
      )
      // 202-800-1238
      or regex.icontains(strings.replace_confusables(body.current_thread.text),
                         '\".*[ilo0-9]{3}-[ilo0-9]{3}-[ilo0-9]{4}.*\"'
      )
      // (202) 800-1238
      or regex.icontains(strings.replace_confusables(body.current_thread.text),
                         '\".*\([ilo0-9]{3}\)\s[ilo0-9]{3}-[ilo0-9]{4}.*\"'
      )
      // (202)-800-1238
      or regex.icontains(strings.replace_confusables(body.current_thread.text),
                         '\".*\([ilo0-9]{3}\)-[ilo0-9]{3}-[ilo0-9]{4}.*\"'
      )
      or ( // 8123456789
        regex.icontains(strings.replace_confusables(body.current_thread.text),
                        '\".*8[ilo0-9]{9}.*\"'
        )
        and regex.icontains(strings.replace_confusables(body.current_thread.text
                            ),
                            '\".*\+[1li].*\"'
        )
      )
    )
    and (
      (
        4 of (
          strings.ilike(body.html.inner_text, '*"*you did not*"*'),
          strings.ilike(body.html.inner_text, '*"*is not for*"*'),
          strings.ilike(body.html.inner_text, '*"*done by you*"*'),
          regex.icontains(body.html.inner_text, "\".*didn\'t ma[kd]e this.*\""),
          strings.ilike(body.html.inner_text, '*"*Fruad Alert*"*'),
          strings.ilike(body.html.inner_text, '*"*Fraud Alert*"*'),
          strings.ilike(body.html.inner_text, '*"*fraudulent*"*'),
          strings.ilike(body.html.inner_text, '*"*Zelle*"*'),
          strings.ilike(body.html.inner_text, '*"*subscription*"*'),
          strings.ilike(body.html.inner_text, '*"*antivirus*"*'),
          strings.ilike(body.html.inner_text, '*"*order*"*'),
          strings.ilike(body.html.inner_text, '*"*support*"*'),
          strings.ilike(body.html.inner_text, '*"*sincerely apologize*"*'),
          strings.ilike(body.html.inner_text, '*"*receipt*"*'),
          strings.ilike(body.html.inner_text, '*"*invoice*"*'),
          strings.ilike(body.html.inner_text, '*"*Purchase*"*'),
          strings.ilike(body.html.inner_text, '*"*transaction*"*'),
          strings.ilike(body.html.inner_text, '*"*Market*Value*"*'),
          strings.ilike(body.html.inner_text, '*"*BTC*"*'),
          strings.ilike(body.html.inner_text, '*"*call*"*'),
          strings.ilike(body.html.inner_text, '*"*get in touch with our*"*'),
          strings.ilike(body.html.inner_text, '*"*quickly inform*"*'),
          strings.ilike(body.html.inner_text, '*"*quickly reach*"*'),
          strings.ilike(body.html.inner_text,
                        '*"*detected unusual transactions*'
          ),
          strings.ilike(body.html.inner_text,
                        '*"*without your authorization*"*'
          ),
          strings.ilike(body.html.inner_text, '*"*cancel*"*'),
          strings.ilike(body.html.inner_text, '*"*renew*"*'),
          strings.ilike(body.html.inner_text, '*"*refund*"*'),
          strings.ilike(body.html.inner_text, '*"*+1*"*'),
          regex.icontains(body.html.inner_text, '\"help.{0,3}desk'),
          strings.ilike(body.html.inner_text, '*"* your funds*"*'),
          strings.ilike(body.html.inner_text, '*"* your checking*"*'),
          strings.ilike(body.html.inner_text, '*"* your saving*"*'),
          strings.ilike(body.html.inner_text, '*"*transfer*"*'),
          strings.ilike(body.html.inner_text, '*"*secure your account*"*'),
          strings.ilike(body.html.inner_text, '*"*recover your *"*'),
        )
      )
      or regex.icontains(body.current_thread.text,
                         'note from.{0,50}(?:call
| reach
| contact
| paypal)'
      )
      or any(ml.nlu_classifier(body.current_thread.text).intents,
             .name == "callback_scam"
      )
      or (
        // Unicode confusables words obfuscated in note
        regex.icontains(body.html.inner_text,
                        '\+𝟭
| 𝗽𝗮𝘆𝗺𝗲𝗻𝘁
| 𝗛𝗲𝗹𝗽 𝗗𝗲𝘀𝗸
| 𝗿𝗲𝗳𝘂𝗻𝗱
| 𝗮𝗻𝘁𝗶𝘃𝗶𝗿𝘂𝘀
| 𝗰𝗮𝗹𝗹
| 𝗰𝗮𝗻𝗰𝗲𝗹'
        )
      )
      or strings.ilike(body.html.inner_text, '*"*kindly*"*')
    )
  )
)

Field Validations

Loading…

Comments (0)

Loading comments...