• Sublime Core Feed
Low Severity

Brand impersonation: File sharing notification with template artifacts

Description

Detects messages impersonating file sharing services that contain template artifacts such as placeholder comments, incomplete HTML elements, and development remnants. The message includes 'shared with you' language and exhibits multiple indicators of being generated from a malicious template including HTML comments with development terms, broken anchor tags, and filename elements that closely match the subject line.

References

No references.

Sublime Security
Created Jan 23rd, 2026 • Last updated Jan 23rd, 2026
Source
type.inbound
and strings.icontains(body.current_thread.text, 'shared with you')
// we detect a file sharing logo with high confidence
and any(ml.logo_detect(file.message_screenshot()).brands,
        .name in ('Microsoft', 'Dropbox', 'Google') and .confidence == "high"
)
and 2 of (
  // the subject is very similar to the name of the file-name html class
  any(html.xpath(body.html, '//span[@class="file-name"]').nodes,
      strings.ilevenshtein(.display_text, subject.subject) < 15
  ),
  // we detect a href to a # implying a neglected placeholder
  any(html.xpath(body.html, '//a[@href="#"]').nodes, .raw is not null),
  // we detect "ai-esque" comments
  any(html.xpath(body.html, '//comment()').nodes,
      regex.icontains(.raw, '(optional|section|placeholder|todo|fixme)')
  ),
  // recipients local part is in the body of the message
  any(recipients.to,
      strings.icontains(body.current_thread.text, .email.local_part)
  ),
  strings.icontains(body.html.raw, 'if the button does not work')
)
// and cred theft/bec high confidence
and any(ml.nlu_classifier(body.current_thread.text).intents,
        .name in ("cred_theft", "bec") and .confidence == "high"
)
// not sent from legitimate Microsoft emails as long as auth passes
and not (
  sender.email.email in (
    'no-reply@outlook.mail.microsoft',
    'azuredevops@microsoft.com'
  )
  and headers.auth_summary.dmarc.pass
)
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