Cisco SEG - Unscannable attacment

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Id	c66b8ced-8c76-415b-a0f3-08c7030a857d
Rulename	Cisco SEG - Unscannable attacment
Description	Detects unscannable attachments in mails.
Severity	Medium
Tactics	InitialAccess
Techniques	T1566
Required data connectors	CefAma
Kind	Scheduled
Query frequency	1h
Query period	1h
Trigger threshold	0
Trigger operator	gt
Source Uri	https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/CiscoSEG/Analytic Rules/CiscoSEGUnscannableAttachment.yaml
Version	1.0.3
Arm template	c66b8ced-8c76-415b-a0f3-08c7030a857d.json

KQL

CiscoSEGEvent
| where NetworkDirection =~ 'Incoming'
| where tostring(AdditionalFields) has 'ESAAMPVerdict'
| extend amp_verdict = extract(@'ESAAMPVerdict":"(NOT_EVALUATED|CLEAN|FA_PENDING|UNKNOWN|SKIPPED|UNSCANNABLE|LOW_RISK|MALICIOUS)"', 1, tostring(AdditionalFields))
| where amp_verdict =~ 'UNSCANNABLE'
| extend AccountCustomEntity = DstUserName

YAML

name: Cisco SEG - Unscannable attacment
id: c66b8ced-8c76-415b-a0f3-08c7030a857d
description: |
    'Detects unscannable attachments in mails.'
triggerThreshold: 0
entityMappings:
- fieldMappings:
  - columnName: AccountCustomEntity
    identifier: Name
  entityType: Account
version: 1.0.3
triggerOperator: gt
query: |
  CiscoSEGEvent
  | where NetworkDirection =~ 'Incoming'
  | where tostring(AdditionalFields) has 'ESAAMPVerdict'
  | extend amp_verdict = extract(@'ESAAMPVerdict":"(NOT_EVALUATED|CLEAN|FA_PENDING|UNKNOWN|SKIPPED|UNSCANNABLE|LOW_RISK|MALICIOUS)"', 1, tostring(AdditionalFields))
  | where amp_verdict =~ 'UNSCANNABLE'
  | extend AccountCustomEntity = DstUserName  
tactics:
- InitialAccess
kind: Scheduled
queryFrequency: 1h
severity: Medium
queryPeriod: 1h
requiredDataConnectors:
- dataTypes:
  - CommonSecurityLog
  connectorId: CefAma
status: Available
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/CiscoSEG/Analytic Rules/CiscoSEGUnscannableAttachment.yaml
relevantTechniques:
- T1566

ARM