Ping Federate - Unusual mail domain

let known_domains = 
PingFederateEvent
| where TimeGenerated between (ago(14d) .. (1d))
| extend email = extract(@'email=(.*?),.*', 1, AdditionalExtensions)
| extend m_domain = extract(@'@(.*)', 1, email)
| where isnotempty(m_domain)
| summarize makeset(m_domain);
PingFederateEvent
| extend email = extract(@'email=(.*?),.*', 1, AdditionalExtensions)
| extend m_domain = extract(@'@(.*)', 1, email)
| where isnotempty(m_domain)
| where m_domain !in (known_domains)
| extend AccountCustomEntity = DstUserName
| extend IpCustomEntity = SrcIpAddr

name: Ping Federate - Unusual mail domain.
kind: Scheduled
tactics:
- InitialAccess
triggerThreshold: 0
triggerOperator: gt
version: 1.0.3
status: Available
queryFrequency: 1h
id: dc79de7d-2590-4852-95fb-f8e02b34f4da
requiredDataConnectors:
- connectorId: CefAma
  dataTypes:
  - CommonSecurityLog
relevantTechniques:
- T1078
description: |
    'Detects unusual mail domain in authentication requests.'
entityMappings:
- entityType: Account
  fieldMappings:
  - columnName: AccountCustomEntity
    identifier: Name
- entityType: IP
  fieldMappings:
  - columnName: IpCustomEntity
    identifier: Address
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/PingFederate/Analytic Rules/PingFederateUnusualMailDomain.yaml
queryPeriod: 14d
severity: Medium
query: |
  let known_domains = 
  PingFederateEvent
  | where TimeGenerated between (ago(14d) .. (1d))
  | extend email = extract(@'email=(.*?),.*', 1, AdditionalExtensions)
  | extend m_domain = extract(@'@(.*)', 1, email)
  | where isnotempty(m_domain)
  | summarize makeset(m_domain);
  PingFederateEvent
  | extend email = extract(@'email=(.*?),.*', 1, AdditionalExtensions)
  | extend m_domain = extract(@'@(.*)', 1, email)
  | where isnotempty(m_domain)
  | where m_domain !in (known_domains)
  | extend AccountCustomEntity = DstUserName
  | extend IpCustomEntity = SrcIpAddr