Cisco SEG - Suspicious sender domain

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Id	ef0a253c-95b5-48e1-8ebc-dbeb073b9338
Rulename	Cisco SEG - Suspicious sender domain
Description	Detects suspicious sender domain age.
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/CiscoSEGSuspiciousSenderDomain.yaml
Version	1.0.3
Arm template	ef0a253c-95b5-48e1-8ebc-dbeb073b9338.json

KQL

CiscoSEGEvent
| where NetworkDirection =~ 'Incoming'
| extend rec_domain = extract(@'@(.*)', 1, DstUserName)
| extend s_domain = extract(@'@(.*)', 1, SrcUserName)
| where s_domain != rec_domain
| where tostring(AdditionalFields) has 'ESASDRDomainAge'
| extend domain_age = extract(@'ESASDRDomainAge":"(.*days)"', 1, tostring(AdditionalFields))
| extend yy = toint(extract(@'(\d+)\syears', 1, domain_age))
| extend mm = toint(extract(@'(\d+)\smonths', 1, domain_age))
| extend dd = toint(extract(@'(\d+)\sdays', 1, domain_age))
| where isempty(yy)
| where isempty(mm) or mm <= 2
| extend AccountCustomEntity = SrcUserName

YAML

description: |
    'Detects suspicious sender domain age.'
version: 1.0.3
triggerThreshold: 0
tactics:
- InitialAccess
queryPeriod: 1h
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/CiscoSEG/Analytic Rules/CiscoSEGSuspiciousSenderDomain.yaml
triggerOperator: gt
status: Available
id: ef0a253c-95b5-48e1-8ebc-dbeb073b9338
name: Cisco SEG - Suspicious sender domain
queryFrequency: 1h
severity: Medium
kind: Scheduled
entityMappings:
- fieldMappings:
  - columnName: AccountCustomEntity
    identifier: Name
  entityType: Account
relevantTechniques:
- T1566
query: |
  CiscoSEGEvent
  | where NetworkDirection =~ 'Incoming'
  | extend rec_domain = extract(@'@(.*)', 1, DstUserName)
  | extend s_domain = extract(@'@(.*)', 1, SrcUserName)
  | where s_domain != rec_domain
  | where tostring(AdditionalFields) has 'ESASDRDomainAge'
  | extend domain_age = extract(@'ESASDRDomainAge":"(.*days)"', 1, tostring(AdditionalFields))
  | extend yy = toint(extract(@'(\d+)\syears', 1, domain_age))
  | extend mm = toint(extract(@'(\d+)\smonths', 1, domain_age))
  | extend dd = toint(extract(@'(\d+)\sdays', 1, domain_age))
  | where isempty(yy)
  | where isempty(mm) or mm <= 2
  | extend AccountCustomEntity = SrcUserName  
requiredDataConnectors:
- dataTypes:
  - CommonSecurityLog
  connectorId: CefAma

ARM