Medium Severity
Attachment: EML with Suspicious Indicators
Description
Attached EML contains suspicious indicators, such as a missing sender email or short HTML body.
References
No references.
Sublime Security
Created Nov 19th, 2024 • Last updated Nov 19th, 2024
Feed Source
Sublime Core Feed
Source
type.inbound
and length(attachments) == 1
and (
length(body.current_thread.text) < 300
or body.current_thread.text is null
or any(ml.nlu_classifier(body.current_thread.text).intents,
.name in ("cred_theft", "steal_pii")
)
)
and not any(ml.nlu_classifier(body.current_thread.text).intents,
.name == "benign" and .confidence == "high"
)
and any(attachments,
(.file_extension == "eml" or .content_type == "message/rfc822")
and (
// suspicious indicators
file.parse_eml(.).sender.email.email == ""
or length(file.parse_eml(.).body.html.raw) < 10
or length(file.parse_eml(.).headers.hops) < 2
)
and not (
all(file.parse_eml(.).body.links,
.href_url.domain.root_domain in ("aka.ms", "office365.com")
or .href_url.url == "#additionalatt"
)
and strings.icontains(file.parse_eml(.).body.current_thread.text,
"We’re making sure your attachments are safe"
)
)
and file.parse_eml(.).sender.email.domain.root_domain not in $org_domains
)
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
)
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