Digital Guardian - Bulk exfiltration to external domain

let threshold = 10;
let corp_domain = dynamic(['example.com']);
DigitalGuardianDLPEvent
| where NetworkApplicationProtocol =~ 'SMTP'
| where isnotempty(inspected_document)
| extend s_domain = extract(@'@(.*)', 1, SrcUserName)
| extend d_domain = extract(@'@(.*)', 1, DstUserName)
| where s_domain in~ (corp_domain)
| where d_domain !in (corp_domain)
| summarize f = dcount(inspected_document) by SrcUserName, DstUserName, bin(TimeGenerated, 30m)
| where  f >= threshold
| extend AccountCustomEntity = SrcUserName

triggerThreshold: 0
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Digital Guardian Data Loss Prevention/Analytic Rules/DigitalGuardianFilesSentToExternalDomain.yaml
relevantTechniques:
- T1048
entityMappings:
- entityType: Account
  fieldMappings:
  - identifier: Name
    columnName: AccountCustomEntity
status: Available
id: 5f75a873-b524-4ba5-a3b8-2c20db517148
query: |
  let threshold = 10;
  let corp_domain = dynamic(['example.com']);
  DigitalGuardianDLPEvent
  | where NetworkApplicationProtocol =~ 'SMTP'
  | where isnotempty(inspected_document)
  | extend s_domain = extract(@'@(.*)', 1, SrcUserName)
  | extend d_domain = extract(@'@(.*)', 1, DstUserName)
  | where s_domain in~ (corp_domain)
  | where d_domain !in (corp_domain)
  | summarize f = dcount(inspected_document) by SrcUserName, DstUserName, bin(TimeGenerated, 30m)
  | where  f >= threshold
  | extend AccountCustomEntity = SrcUserName  
queryPeriod: 1h
name: Digital Guardian - Bulk exfiltration to external domain
version: 1.0.2
severity: Medium
kind: Scheduled
triggerOperator: gt
description: |
    'Detects bulk exfiltration to external domain.'
queryFrequency: 1h
requiredDataConnectors:
- datatypes:
  - Syslog
  connectorId: SyslogAma
tactics:
- Exfiltration