Detection rules › Kusto

Mimecast Secure Email Gateway - Attachment Protect

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: 72264f4f-61fb-4f4f-96c4-635571a376c2
name: Mimecast Secure Email Gateway - Attachment Protect
description: Detect threat for mail attachment under the targeted threat protection
severity: High
requiredDataConnectors:
  - connectorId: MimecastSIEMAPI
    dataTypes:
      - MimecastSIEM_CL
enabled: true
query: MimecastSIEM_CL| where mimecastEventId_s=="mail_ttp_attachment"
queryFrequency: 5m
queryPeriod: 15m
triggerOperator: gt
triggerThreshold: 0
suppressionDuration: 5h
suppressionEnabled: false
tactics:
- Collection
- Exfiltration
- Discovery
- InitialAccess
- Execution
relevantTechniques:
- T1114
- T1566
- T0865
incidentConfiguration:
  createIncident: true
  groupingConfiguration:
    enabled: true
    reopenClosedIncident: false
    lookbackDuration: 1d
    matchingMethod: AllEntities
eventGroupingSettings:
  aggregationKind: SingleAlert
customDetails:
  sha256: sha256_s
  fileName: fileName_s
  MsgId_s: MsgId_s
entityMappings:
- entityType: MailMessage
  fieldMappings:
  - identifier: Sender
    columnName: Sender_s
  - identifier: Recipient
    columnName: Recipient_s
  - identifier: Subject
    columnName: Subject_s
- entityType: IP
  fieldMappings:
  - identifier: Address
    columnName: IP_s
version: 1.0.1
kind: Scheduled

Stages and Predicates

Stage 1: source

MimecastSIEM_CL

Stage 2: where

| where mimecastEventId_s=="mail_ttp_attachment"

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
mimecastEventId_seq
  • mail_ttp_attachment transforms: cased