Medium Severity
Suspicious Recipients pattern with no Compauth pass and suspicious content
Description
Detects messages with undisclosed recipients (likely all bcc), where the Compauth verdict is not 'pass', and ML has identified suspicious language or credential phishing links.
References
No references.
Sublime Security
Created Aug 17th, 2023 • Last updated Jul 16th, 2025
Feed Source
Sublime Core Feed
Source
type.inbound
and (length(recipients.to) == 0 or all(recipients.to, .display_name == "Undisclosed recipients"))
and length(recipients.cc) == 0
and length(recipients.bcc) == 0
and 2 of (
(
any(headers.hops,
.authentication_results.compauth.verdict is not null
and .authentication_results.compauth.verdict not in ("pass", "softpass")
)
),
(
any(ml.nlu_classifier(body.current_thread.text).intents,
.name in ("bec", "cred_theft", "advance_fee") and .confidence == "high"
)
),
(
any(body.links,
any([ml.link_analysis(.)],
.credphish.disposition == "phishing" and .credphish.confidence in ("high")
)
)
)
)
and (
profile.by_sender().prevalence in ("new", "outlier")
or (
profile.by_sender().any_messages_malicious_or_spam
and not profile.by_sender().any_messages_benign
)
)
// negate highly trusted sender domains unless they fail DMARC authentication
and (
(
sender.email.domain.root_domain in $high_trust_sender_root_domains
and not headers.auth_summary.dmarc.pass
)
or sender.email.domain.root_domain not in $high_trust_sender_root_domains
)
Playground
Test against your own EMLs or sample data.