Medium Severity
Link: Credential Phishing link with Undisclosed Recipients
Description
This rule detects messages with "Undisclosed Recipients" that contain a link to a credential phishing page.
References
No references.
Sublime Security
Created Aug 17th, 2023 • Last updated Jul 16th, 2025
Feed Source
Sublime Core Feed
Source
type.inbound
and (
// No Recipients
length(recipients.to) == 0
or all(recipients.to, .display_name == "Undisclosed recipients")
)
and length(recipients.cc) == 0
and length(recipients.bcc) == 0
and any(body.links,
ml.link_analysis(.).credphish.disposition == "phishing"
and ml.link_analysis(.).credphish.confidence in ("medium", "high")
)
// 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
)
and not profile.by_sender().solicited
and not profile.by_sender().any_messages_benign
Playground
Test against your own EMLs or sample data.