E.3.9.1 prerequisite. Rules R0031-R0040 now use lifter:behavioral_*,
R0041 (open_relay) uses lifter:email_open_relay; the rest of the email,
canary, and intel cohorts already conformed. Each lifter at E.3.9-E.3.12
will claim its rules via str.startswith('lifter:<owner>_'), keeping the
ownership routing explicit and trivially extensible.
R0001-R0006 / R0030 lifter:* rules are E.3.13 (Identity/Credential)
territory and stay as-is.
25 lines
528 B
YAML
25 lines
528 B
YAML
rule_id: R0041
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rule_version: 1
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name: open_relay_abuse
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description: |
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High RCPT count with a foreign From — abuse of an open relay to
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push outbound mail. EmailLifter (E.3.12).
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applies_to:
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- email
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match:
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kind: lifter:email_open_relay
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rcpt_threshold: 10
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require_foreign_from: true
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emits:
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- tactic: TA0040
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technique_id: T1496
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confidence: 0.85
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- tactic: TA0042
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technique_id: T1586
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sub_technique_id: T1586.002
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confidence: 0.85
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evidence_fields:
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- rcpt_count
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- from_domain
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- mail_from_domain
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