Cisco SEG - Unexpected link

Back


Id	9cb4a02d-3708-42ba-b33b-0fdd360ce4b6
Rulename	Cisco SEG - Unexpected link
Description	Detects mails with suspicious links.
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/CiscoSEGUnclassifiedLink.yaml
Version	1.0.3
Arm template	9cb4a02d-3708-42ba-b33b-0fdd360ce4b6.json

KQL

let u_cat = dynamic(['Unclassified']);
CiscoSEGEvent
| where NetworkDirection =~ 'Incoming'
| where tostring(AdditionalFields) has 'ESAURLDetails'
| extend link_cat = extract(@"'Category': '(.*?)'", 1, tostring(AdditionalFields))
| where link_cat in~ (u_cat)
| extend AccountCustomEntity = DstUserName

YAML

relevantTechniques:
- T1566
entityMappings:
- entityType: Account
  fieldMappings:
  - columnName: AccountCustomEntity
    identifier: Name
version: 1.0.3
id: 9cb4a02d-3708-42ba-b33b-0fdd360ce4b6
severity: Medium
kind: Scheduled
queryFrequency: 1h
description: |
    'Detects mails with suspicious links.'
requiredDataConnectors:
- connectorId: CefAma
  dataTypes:
  - CommonSecurityLog
triggerOperator: gt
name: Cisco SEG - Unexpected link
tactics:
- InitialAccess
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/CiscoSEG/Analytic Rules/CiscoSEGUnclassifiedLink.yaml
triggerThreshold: 0
queryPeriod: 1h
query: |
  let u_cat = dynamic(['Unclassified']);
  CiscoSEGEvent
  | where NetworkDirection =~ 'Incoming'
  | where tostring(AdditionalFields) has 'ESAURLDetails'
  | extend link_cat = extract(@"'Category': '(.*?)'", 1, tostring(AdditionalFields))
  | where link_cat in~ (u_cat)
  | extend AccountCustomEntity = DstUserName  
status: Available

ARM