Cisco SEG - Suspicious link

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Id	506291dd-8050-4c98-a92f-58e376080a0a
Rulename	Cisco SEG - Suspicious link
Description	Detects mails with suspicious links.
Severity	High
Tactics	InitialAccess
Techniques	T1566
Required data connectors	CefAma
Kind	Scheduled
Query frequency	15m
Query period	15m
Trigger threshold	0
Trigger operator	gt
Source Uri	https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/CiscoSEG/Analytic Rules/CiscoSEGSuspiciousLink.yaml
Version	1.0.3
Arm template	506291dd-8050-4c98-a92f-58e376080a0a.json

KQL

let bl_cat = dynamic(['Adult', 'Hacking', 'Cheating and Plagiarism', 'Child Abuse Content', 'Dating', 'Illegal Activities', 'Pornography']);
CiscoSEGEvent
| where NetworkDirection =~ 'Incoming'
| where tostring(AdditionalFields) has 'ESAURLDetails'
| extend link_cat = extract(@"'Category': '(.*?)'", 1, tostring(AdditionalFields))
| where link_cat in~ (bl_cat)
| extend AccountCustomEntity = DstUserName

YAML

status: Available
queryFrequency: 15m
id: 506291dd-8050-4c98-a92f-58e376080a0a
tactics:
- InitialAccess
entityMappings:
- fieldMappings:
  - columnName: AccountCustomEntity
    identifier: Name
  entityType: Account
requiredDataConnectors:
- connectorId: CefAma
  dataTypes:
  - CommonSecurityLog
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/CiscoSEG/Analytic Rules/CiscoSEGSuspiciousLink.yaml
version: 1.0.3
query: |
  let bl_cat = dynamic(['Adult', 'Hacking', 'Cheating and Plagiarism', 'Child Abuse Content', 'Dating', 'Illegal Activities', 'Pornography']);
  CiscoSEGEvent
  | where NetworkDirection =~ 'Incoming'
  | where tostring(AdditionalFields) has 'ESAURLDetails'
  | extend link_cat = extract(@"'Category': '(.*?)'", 1, tostring(AdditionalFields))
  | where link_cat in~ (bl_cat)
  | extend AccountCustomEntity = DstUserName  
description: |
    'Detects mails with suspicious links.'
relevantTechniques:
- T1566
triggerThreshold: 0
queryPeriod: 15m
triggerOperator: gt
name: Cisco SEG - Suspicious link
severity: High
kind: Scheduled

ARM