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Detection rules › Kusto

Mimecast Secure Email Gateway - Attachment Protect

Status
available
Severity
high
Time window
15m
Source
github.com/Azure/Azure-Sentinel

'Detect threat for mail attachment under the targeted threat protection.'

MITRE ATT&CK coverage

TacticTechniques
Initial AccessT1566 Phishing
CollectionT1114 Email Collection
Initial AccessT0865 Spearphishing Attachment

Rule body kusto

id: 72bd7b0c-493c-4fa5-8a95-7f6376b6cfb2
name: Mimecast Secure Email Gateway - Attachment Protect
description: |
  'Detect threat for mail attachment under the targeted threat protection.'
severity: High
status: Available
requiredDataConnectors:
  - connectorId: MimecastSEGAPI
    dataTypes:
      - MimecastCG
enabled: true
queryFrequency: 15m
queryPeriod: 15m
triggerOperator: gt
triggerThreshold: 0
tactics:
- Collection
- Exfiltration
- Discovery
- InitialAccess
- Execution
relevantTechniques:
- T1114
- T1566
- T0865
query: |
  MimecastCG
  | where Type == "email_ttp_ap"
  | extend  SenderEnvelope = ['Sender Envelope']  , SenderIp = ['Sender IP']
suppressionDuration: 5h
suppressionEnabled: false
incidentConfiguration:
  createIncident: true
  groupingConfiguration:
    enabled: true
    reopenClosedIncident: false
    lookbackDuration: P7D
    matchingMethod: AllEntities
eventGroupingSettings:
  aggregationKind: AlertPerResult
entityMappings:
- entityType: MailMessage
  fieldMappings:
  - identifier: Sender
    columnName: SenderEnvelope
  - identifier: Recipient
    columnName: Recipients
  - identifier: Subject
    columnName: Subject
- entityType: IP
  fieldMappings:
  - identifier: Address
    columnName: SenderIp
version: 1.0.0
kind: Scheduled

Stages and Predicates

Stage 1: source

MimecastCG

Stage 2: where

| where Type == "email_ttp_ap"

Stage 3: extend

| extend  SenderEnvelope = ['Sender Envelope']  , SenderIp = ['Sender IP']

Indicators

Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.

FieldKindValues
Typeeq
  • email_ttp_ap transforms: cased

Output fields

Fields the rule emits when it matches. Chronicle authors list these in the outcome block; they appear on the detection and $risk_score drives alerting. Sentinel / Defender XDR rules build them up through project / summarize / extend stages. Sentinel maps these into alert fields via entityMappings and customDetails; Defender XDR custom detections surface them as alert fields directly.

FieldSource
SenderEnvelopeextend
SenderIpextend