Detection rules › Sublime MQL

Service abuse: Monday.com infrastructure with phishing intent

Severity
high
Type
rule
Source
github.com/sublime-security/sublime-rules

Detects unauthorized use of Monday.com tracking links in messages, attachments, or QR codes from unusual senders who lack proper authentication. Excludes legitimate replies and messages from trusted domains with valid DMARC.

Threat classification

Sublime's own taxonomy (not MITRE ATT&CK).

CategoryValues
Attack typesCredential Phishing
Tactics and techniquesEvasion, Social engineering, QR code

Event coverage

Rule body MQL

type.inbound
and (
  (
    length(body.links) < 15
    and any(body.links,
            'monday_tracker' in .href_url.rewrite.encoders
            and .href_url.scheme != "mailto"
    )
  )
  or (
    length(attachments) <= 3
    and (
      any(attachments,
          (.file_type in $file_types_images or .file_type == "pdf")
          //
          // 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 any(beta.scan_qr(.).items,
                  .type is not null
                  and 'monday_tracker' in .url.rewrite.encoders
                  and .url.scheme != "mailto"
          )
          //
          // 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
          //
          // exclude images taken with mobile cameras and screenshots from android
          and not any(beta.parse_exif(.).fields,
                      .key == "Model"
                      or (
                        .key == "Software"
                        and strings.starts_with(.value, "Android")
                      )
          )
          // exclude images taken with mobile cameras and screenshots from Apple
          and not any(beta.parse_exif(.).fields,
                      .key == "DeviceManufacturer"
                      and .value == "Apple Computer Inc."
          )
      )
    )
  )
  or (
    length(attachments) == 0
    and (
      //
      // 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
      //
      beta.parse_exif(file.message_screenshot()).image_height < 2000
      and beta.parse_exif(file.message_screenshot()).image_width < 2000
      and beta.scan_qr(file.message_screenshot()).found
      and any(beta.scan_qr(file.message_screenshot()).items,
              .type is not null
              and 'monday_tracker' in .url.rewrite.encoders
              and .url.scheme != "mailto"
      )
    )
  )
  or (
    length(attachments) <= 3
    and (
      any(attachments,
          (
            .file_type in ("pdf")
            or .file_extension in ("pdf", "eml")
            or .file_extension in $file_extensions_macros
            or .content_type in ("message/rfc822")
          )
          and any(file.explode(.),
                  any(.scan.url.urls, 'monday_tracker' in .rewrite.encoders)
          )
      )
    )
  )
)
// negate messages that traverse monday.com infra
and not (
  any(headers.domains, strings.ends_with(.domain, "mail.monday.com"))
  or (
    strings.iends_with(headers.message_id, '@monday-mail.com>')
    and any(headers.hops,
            any(.fields,
                .name =~ "Content-Type"
                and strings.iends_with(.value, 'mondaymailcom_"')
            )
    )
    and any(headers.hops, any(.fields, .name =~ "x-monday-crm"))
  )
)
and not (
  headers.auth_summary.dmarc.details.from.root_domain == "monday.com"
  and headers.auth_summary.spf.pass
  and headers.auth_summary.dmarc.pass
)
and any(ml.nlu_classifier(body.current_thread.text).intents,
        .name != "benign" and .confidence in ("medium", "high")
)
// negating legit replies
and not (
  (subject.is_reply or subject.is_forward)
  and (length(headers.references) > 0 and headers.in_reply_to is not null)
)
// negate graymail and newsletters
and not (
  any(ml.nlu_classifier(body.current_thread.text).topics,
      .name in~ (
        "Advertising and Promotions",
        "B2B Cold Outreach",
        "Newsletters and Digests",
        "Events and Webinars"
      )
      and .confidence != "low"
  )
)
and (
  // negate highly trusted sender domains unless they fail DMARC authentication
  not (
    sender.email.domain.root_domain in $high_trust_sender_root_domains
    and coalesce(headers.auth_summary.dmarc.pass, false)
  )
  // salesforce has been abused to send phishing campaigns leveraging monday.com infrastructure abuse
  or sender.email.domain.root_domain in ("salesforce.com")
)

Detection logic

Scope: inbound message.

Detects unauthorized use of Monday.com tracking links in messages, attachments, or QR codes from unusual senders who lack proper authentication. Excludes legitimate replies and messages from trusted domains with valid DMARC.

  1. inbound message
  2. any of:
    • all of:
      • length(body.links) < 15
      • any of body.links where all hold:
        • .href_url.rewrite.encoders contains 'monday_tracker'
        • .href_url.scheme is not 'mailto'
    • all of:
      • length(attachments) ≤ 3
      • any of attachments where all hold:
        • any of:
          • .file_type in $file_types_images
          • .file_type is 'pdf'
        • any of beta.scan_qr(.).items where all hold:
          • .type is set
          • .url.rewrite.encoders contains 'monday_tracker'
          • .url.scheme is not 'mailto'
        • not:
          • any of beta.parse_exif(.).fields where any holds:
            • .key is 'Model'
            • all of:
              • .key is 'Software'
              • .value starts with 'Android'
        • not:
          • any of beta.parse_exif(.).fields where all hold:
            • .key is 'DeviceManufacturer'
            • .value is 'Apple Computer Inc.'
    • all of:
      • length(attachments) is 0
      • all of:
        • beta.parse_exif(file.message_screenshot()).image_height < 2000
        • beta.parse_exif(file.message_screenshot()).image_width < 2000
        • beta.scan_qr(file.message_screenshot()).found
        • any of beta.scan_qr(file.message_screenshot()).items where all hold:
          • .type is set
          • .url.rewrite.encoders contains 'monday_tracker'
          • .url.scheme is not 'mailto'
    • all of:
      • length(attachments) ≤ 3
      • any of attachments where all hold:
        • any of:
          • .file_type in ('pdf')
          • .file_extension in ('pdf', 'eml')
          • .file_extension in $file_extensions_macros
          • .content_type in ('message/rfc822')
        • any of file.explode(.) where:
          • any of .scan.url.urls where:
            • .rewrite.encoders contains 'monday_tracker'
  3. none of:
    • any of headers.domains where:
      • .domain ends with 'mail.monday.com'
    • all of:
      • headers.message_id ends with '@monday-mail.com>'
      • any of headers.hops where:
        • any of .fields where all hold:
          • .name is 'Content-Type'
          • .value ends with 'mondaymailcom_"'
      • any of headers.hops where:
        • any of .fields where:
          • .name is 'x-monday-crm'
  4. not:
    • all of:
      • headers.auth_summary.dmarc.details.from.root_domain is 'monday.com'
      • headers.auth_summary.spf.pass
      • headers.auth_summary.dmarc.pass
  5. any of ml.nlu_classifier(body.current_thread.text).intents where all hold:
    • .name is not 'benign'
    • .confidence in ('medium', 'high')
  6. not:
    • all of:
      • any of:
        • subject.is_reply
        • subject.is_forward
      • all of:
        • length(headers.references) > 0
        • headers.in_reply_to is set
  7. not:
    • any of ml.nlu_classifier(body.current_thread.text).topics where all hold:
      • .name in ('Advertising and Promotions', 'B2B Cold Outreach', 'Newsletters and Digests', 'Events and Webinars')
      • .confidence is not 'low'
  8. any of:
    • not:
      • all of:
        • sender.email.domain.root_domain in $high_trust_sender_root_domains
        • coalesce(headers.auth_summary.dmarc.pass)
    • sender.email.domain.root_domain in ('salesforce.com')

Inspects: attachments[].content_type, attachments[].file_extension, attachments[].file_type, body.current_thread.text, body.links, body.links[].href_url.rewrite.encoders, body.links[].href_url.scheme, headers.auth_summary.dmarc.details.from.root_domain, headers.auth_summary.dmarc.pass, headers.auth_summary.spf.pass, headers.domains, headers.domains[].domain, headers.hops, headers.hops[].fields, headers.hops[].fields[].name, headers.hops[].fields[].value, headers.in_reply_to, headers.message_id, headers.references, sender.email.domain.root_domain, subject.is_forward, subject.is_reply, type.inbound. Sensors: beta.parse_exif, beta.scan_qr, file.explode, file.message_screenshot, ml.nlu_classifier, strings.ends_with, strings.iends_with, strings.starts_with. Reference lists: $file_extensions_macros, $file_types_images, $high_trust_sender_root_domains.

Indicators matched (27)

FieldMatchValue
body.links[].href_url.rewrite.encoderscontainsmonday_tracker
attachments[].file_typeequalspdf
beta.scan_qr(attachments[]).items[].url.rewrite.encoderscontainsmonday_tracker
beta.parse_exif(attachments[]).fields[].keyequalsModel
beta.parse_exif(attachments[]).fields[].keyequalsSoftware
strings.starts_withprefixAndroid
beta.parse_exif(attachments[]).fields[].keyequalsDeviceManufacturer
beta.parse_exif(attachments[]).fields[].valueequalsApple Computer Inc.
beta.scan_qr(file.message_screenshot()).items[].url.rewrite.encoderscontainsmonday_tracker
attachments[].file_typememberpdf
attachments[].file_extensionmemberpdf
attachments[].file_extensionmembereml
15 more
attachments[].content_typemembermessage/rfc822
file.explode(attachments[])[].scan.url.urls[].rewrite.encoderscontainsmonday_tracker
strings.ends_withsuffixmail.monday.com
strings.iends_withsuffix@monday-mail.com>
headers.hops[].fields[].nameequalsContent-Type
strings.iends_withsuffixmondaymailcom_"
headers.hops[].fields[].nameequalsx-monday-crm
headers.auth_summary.dmarc.details.from.root_domainequalsmonday.com
ml.nlu_classifier(body.current_thread.text).intents[].confidencemembermedium
ml.nlu_classifier(body.current_thread.text).intents[].confidencememberhigh
ml.nlu_classifier(body.current_thread.text).topics[].namememberAdvertising and Promotions
ml.nlu_classifier(body.current_thread.text).topics[].namememberB2B Cold Outreach
ml.nlu_classifier(body.current_thread.text).topics[].namememberNewsletters and Digests
ml.nlu_classifier(body.current_thread.text).topics[].namememberEvents and Webinars
sender.email.domain.root_domainmembersalesforce.com