High Severity
Lookalike sender domain (untrusted sender)
Description
Sender's domain is a lookalike of one of your organization's domains and is untrusted.
References
No references.
Sublime Security
Created Aug 17th, 2023 • Last updated Jun 3rd, 2024
Feed Source
Sublime Core Feed
Source
type.inbound
and any($org_domains,
length(sender.email.domain.sld) > 3
// this rule can be duplicated in order to tune the threshold
and strings.ilevenshtein(sender.email.domain.domain, .) == 1
and sender.email.domain.domain not in $org_domains
)
and (
(
profile.by_sender().prevalence in ("new", "outlier")
and not profile.by_sender().solicited
)
or (
profile.by_sender().any_messages_malicious_or_spam
and not profile.by_sender().any_false_positives
)
)
// 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().any_false_positives
Playground
Test against your own EMLs or sample data.