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Restructured "Attach: Sus Employee Lure" rule #4369

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Restructured "Attach: Sus Employee Lure" rule #4369

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756ff0f
Restructured "Attach: Sus Employee Lure" rule
missingn0pe Apr 17, 2026
f2bf594
Resubmitting with correct format
missingn0pe Apr 20, 2026
8a88b77
Updating Attachment: Policy lure attachment rule
missingn0pe Apr 21, 2026
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198 changes: 137 additions & 61 deletions detection-rules/attachment_sus_employee_doc.yml
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Original file line number Diff line number Diff line change
Expand Up @@ -4,98 +4,174 @@ type: "rule"
severity: "medium"
source: |
type.inbound
// NOTE: This rule is designed for these values to match/sync subject.base and file names
// NOTE: mirror ALL changes between subject & attachments
and (
// the subject contains pay related items
// the subject contains pay related keywords
(
strings.icontains(subject.base, 'salary')
or regex.icontains(subject.base, '\bpay(?:out|roll|\b)')
or strings.icontains(subject.base, 'remuneration')
or strings.icontains(subject.base, 'bonus')
or strings.icontains(subject.base, 'incentive')
or strings.icontains(subject.base, 'merit\b')
or strings.icontains(subject.base, 'handbook')
or strings.icontains(subject.base, 'benefits')
or strings.icontains(subject.base, 'earnings')
or strings.icontains(subject.base, 'contract')
or regex.icontains(subject.base, 'empl[o0]yment')
(
strings.icontains(subject.base, "benefits")
and not strings.icontains(subject.base, "fidelity netbenefits")
)
or strings.icontains(subject.base, "bonus")
or (
regex.icontains(subject.base, '(?:\bcomp\b|compensation)')
and not strings.icontains(subject.base, "broker")
)
or strings.icontains(subject.base, "earnings")
or regex.icontains(subject.base, 'empl[o0]y(?:ment|ee)')
or (
strings.icontains(subject.base, "financial")
and not strings.icontains(subject.base, "statement")
)
or strings.icontains(subject.base, "handbook")
or strings.icontains(subject.base, "incentive")
or regex.icontains(subject.base, 'merit\b')
or regex.icontains(subject.base, '\bpay(?:out|roll)?\b')
or strings.icontains(subject.base, "remuneration")
or strings.icontains(subject.base, "salary")
)
and (
strings.icontains(subject.base, 'review')
or strings.icontains(subject.base, 'breakdown')
or strings.icontains(subject.base, 'Access Your')
or strings.icontains(subject.base, 'evaluation')
strings.icontains(subject.base, "access your")
or strings.icontains(subject.base, "acknowledg")
or regex.icontains(subject.base, 'adjust(?:ed|ment)')
or regex.icontains(subject.base, 'amend(?:ed|ment)')
or strings.icontains(subject.base, "appraisal")
or strings.icontains(subject.base, "assessment")
or strings.icontains(subject.base, "breakdown")
or strings.icontains(subject.base, "change")
or strings.icontains(subject.base, "details")
or strings.icontains(subject.base, "distribution")
or regex.icontains(subject.base, 'eval\b')
or strings.icontains(subject.base, 'assessment')
or strings.icontains(subject.base, 'appraisal')
or strings.icontains(subject.base, 'feedback')
or strings.icontains(subject.base, 'performance')
or strings.icontains(subject.base, 'adjustment')
or strings.icontains(subject.base, 'qualification')
or strings.icontains(subject.base, 'increase')
or strings.icontains(subject.base, 'raise')
or strings.icontains(subject.base, 'change')
or strings.icontains(subject.base, 'modification')
or strings.icontains(subject.base, 'distribution')
or strings.icontains(subject.base, 'details')
or strings.icontains(subject.base, "evaluation")
or strings.icontains(subject.base, "feedback")
or strings.icontains(subject.base, "increase")
or strings.icontains(subject.base, "increment")
or strings.icontains(subject.base, "info")
or strings.icontains(subject.base, "modification")
or strings.icontains(subject.base, "notification")
or strings.icontains(subject.base, "performance")
or strings.icontains(subject.base, "plan")
or strings.icontains(subject.base, "qualification")
or strings.icontains(subject.base, "raise")
or (
strings.icontains(subject.base, "review")
and not strings.icontains(subject.base, "preview")
)
or regex.icontains(subject.base, 'revis(?:ed|ion)')
or regex.icontains(subject.base, 'amend(?:ed|ment)')
or regex.icontains(subject.base, 'update(?:d| to)')
or strings.icontains(subject.base, 'plan')
or strings.icontains(subject.base, 'notification')
or strings.icontains(subject.base, "statement")
or regex.icontains(subject.base, 'update(?:d| to)?')
or regex.icontains(subject.base,
'(January|February|March|April|May|June|July|August|September|October|November|December)\s20[2,3]{1}\d{1}'
)
)
// general strings negations
and not (
strings.icontains(subject.base, "error")
or regex.icontains(subject.base, '\bapp(?:lication)?\b')
)
)

// the attachment contains pay related keywords
and 0 < length(attachments) <= 3
and any(attachments,
.file_extension in ("doc", "docx", "docm", "pdf", "pptx")
(
// typical observed extentions
.file_extension in ("doc", "docx", "docm", "pdf", "pptx")
// missing extensions
or .file_extension is null
// magic bytes
or .file_type in ("doc", "docx", "pdf", "pptx")
// attached EML
or (.content_type == "message/rfc822" or .file_extension =~ "eml")
)
and (
strings.icontains(.file_name, 'salary')
or strings.icontains(.file_name, 'compensation')
or regex.icontains(.file_name, '\bpay(?:roll|\b)')
or strings.icontains(.file_name, 'bonus')
or strings.icontains(.file_name, 'incentive')
or strings.icontains(.file_name, 'merit\b')
or strings.icontains(.file_name, 'handbook')
or strings.icontains(.file_name, 'benefits')
or regex.icontains(.file_name, 'empl[o0]yment')
(
strings.icontains(.file_name, "benefits")
and not strings.icontains(.file_name, "fidelity netbenefits")
)
or strings.icontains(.file_name, "bonus")
or (
regex.icontains(.file_name, '(?:\bcomp\b|compensation)')
and not (strings.icontains(.file_name, "broker"))
)
or regex.icontains(.file_name, 'empl[o0]y(?:ment|ee)')
or (
strings.icontains(.file_name, "financial")
and not strings.icontains(.file_name, "statement")
)
or strings.icontains(.file_name, "handbook")
or strings.icontains(.file_name, "incentive")
or regex.icontains(.file_name, 'merit\b')
or regex.icontains(.file_name, '\bpay(?:out|roll)?\b')
or strings.icontains(.file_name, "remuneration")
or strings.icontains(.file_name, "salary")
)
and (
strings.icontains(.file_name, 'review')
or strings.icontains(.file_name, 'evaluation')
strings.icontains(.file_name, "access your")
or strings.icontains(.file_name, "acknowledg")
or regex.icontains(.file_name, 'adjust(?:ed|ment)')
or regex.icontains(.file_name, 'amend(?:ed|ment)')
or strings.icontains(.file_name, "appraisal")
or strings.icontains(.file_name, "assessment")
or strings.icontains(.file_name, "breakdown")
or strings.icontains(.file_name, "change")
or strings.icontains(.file_name, "details")
or strings.icontains(.file_name, "distribution")
or regex.icontains(.file_name, 'eval\b')
or strings.icontains(.file_name, 'assessment')
or strings.icontains(.file_name, 'appraisal')
or strings.icontains(.file_name, 'feedback')
or strings.icontains(.file_name, 'performance')
or strings.icontains(.file_name, 'adjustment')
or strings.icontains(.file_name, 'increase')
or strings.icontains(.file_name, 'increment')
or strings.icontains(.file_name, 'raise')
or strings.icontains(.file_name, 'change')
or strings.icontains(.file_name, 'modification')
or strings.icontains(.file_name, 'distribution')
or strings.icontains(.file_name, 'statement')
or strings.icontains(.file_name, "evaluation")
or strings.icontains(.file_name, "feedback")
or strings.icontains(.file_name, "increase")
or strings.icontains(.file_name, "increment")
or strings.icontains(.file_name, "info")
or strings.icontains(.file_name, "modification")
or strings.icontains(.file_name, "notification")
or strings.icontains(.file_name, "performance")
or strings.icontains(.file_name, "plan")
or strings.icontains(.file_name, "qualification")
or strings.icontains(.file_name, "raise")
or (
strings.icontains(.file_name, "review")
and not strings.icontains(.file_name, "preview")
)
or regex.icontains(.file_name, 'revis(?:ed|ion)')
or regex.icontains(.file_name, 'amend(?:ed|ment)')
or regex.icontains(.file_name, 'adjust(?:ed|ment)')
or regex.icontains(.file_name, 'update(?:d| to)')
or strings.icontains(.file_name, "statement")
or regex.icontains(.file_name, 'update(?:d| to)?')
or regex.icontains(.file_name,
'(January|February|March|April|May|June|July|August|September|October|November|December)\s20[2,3]{1}\d{1}'
)
or strings.icontains(.file_name, 'contract')
or (
// file name contains recipient's email
any(recipients.to,
strings.icontains(..file_name, .email.email)
and .email.domain.valid
)
// file name contains recipient's sld
or any(recipients.to,
strings.icontains(..file_name, .email.domain.sld)
and .email.domain.valid
)
)
)
)

// topic negations
and not any(ml.nlu_classifier(body.current_thread.text).topics,
.name == "Newsletters and Digests"
)

// negate legitimate conversations
and not (
(length(headers.references) > 0 or headers.in_reply_to is not null)
and (subject.is_forward or subject.is_reply)
and length(body.previous_threads) >= 1
)

// negate high trust sender domains unless they fail authentication
and not (
sender.email.domain.root_domain in $high_trust_sender_root_domains
and coalesce(headers.auth_summary.dmarc.pass, false)
)

attack_types:
- "Credential Phishing"
tactics_and_techniques:
Expand Down
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