Low Severity

Body HTML: Comment with 24-character hex token

Description

Detects messages containing HTML comments with exactly 24 hexadecimal characters, which may indicate tracking tokens, session identifiers, or other suspicious embedded data used for evasion or tracking purposes.

References

No references.

Sublime Security
Created Mar 17th, 2026 • Last updated Sep 1st, 2026
Source
type.inbound
and any(html.xpath(body.html, '//comment()').nodes,
        regex.imatch(.raw, '<!--\s*[a-f0-9]{24}\s*-->')
)
and not (
  sender.email.domain.root_domain in $high_trust_sender_root_domains
  and coalesce(headers.auth_summary.dmarc.pass, false)
)
and any(ml.nlu_classifier(body.current_thread.text).intents,
        .name in ("cred_theft", "bec") and .confidence != 'low'
)
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