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Detection rules › Kusto

Mimecast Targeted Threat Protection - Attachment Protect

Status
available
Severity
high
Time window
30m
Source
github.com/Azure/Azure-Sentinel

'Detects a threat for an unsafe attachment in an email.'

MITRE ATT&CK coverage

TacticTechniques
Initial AccessT0865 Spearphishing Attachment

Rule body kusto

id: 617a55be-a8d8-49c1-8687-d19a0231056f
name: Mimecast Targeted Threat Protection - Attachment Protect
description: |
  'Detects a threat for an unsafe attachment in an email.'
severity: High
status: Available
requiredDataConnectors:
  - connectorId: MimecastTTPAPI
    dataTypes:
      - MimecastTTPAttachment
queryFrequency: 30m
queryPeriod: 30m
triggerOperator: gt
triggerThreshold: 0
tactics:
- InitialAccess
- Discovery
relevantTechniques:
- T0865
query: |
  MimecastTTPAttachment
  | where Result != "safe"
  | extend SenderAddress = ['Sender Address'] ,RecipientAddress = ['Recipient Address']
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: SenderAddress
      - identifier: Recipient
        columnName: RecipientAddress
      - identifier: Subject
        columnName: Subject
version: 1.0.0
kind: Scheduled

Stages and Predicates

Stage 1: source

MimecastTTPAttachment

Stage 2: where

| where Result != "safe"

Stage 3: extend

| extend SenderAddress = ['Sender Address'] ,RecipientAddress = ['Recipient Address']

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
Resultne
  • safe 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
RecipientAddressextend
SenderAddressextend