Security Event log cleared

id: 80da0a8f-cfe1-4cd0-a895-8bc1771a720e
name: Security Event log cleared
description: |
  'Checks for event id 1102 which indicates the security event log was cleared.
  It uses Event Source Name "Microsoft-Windows-Eventlog" to avoid generating false positives from other sources, like AD FS servers for instance.'
severity: Medium
status: Available
requiredDataConnectors:
  - connectorId: SecurityEvents
    dataTypes:
      - SecurityEvent
  - connectorId: WindowsSecurityEvents
    dataTypes:
      - SecurityEvent
  - connectorId: WindowsForwardedEvents
    dataTypes:
      - WindowsEvent
queryFrequency: 1d
queryPeriod: 1d
triggerOperator: gt
triggerThreshold: 0
tactics:
  - DefenseEvasion
relevantTechniques:
  - T1070
query: |
  (union isfuzzy=true
  (
  SecurityEvent
  | where EventID == 1102 and EventSourceName =~ "Microsoft-Windows-Eventlog"
  | summarize StartTimeUtc = min(TimeGenerated), EndTimeUtc = max(TimeGenerated), EventCount = count() by Computer, Account, EventID, Activity
  ),
  (
  WindowsEvent
  | where EventID == 1102 and Provider =~ "Microsoft-Windows-Eventlog"
  | extend Account =  strcat(tostring(EventData.SubjectDomainName),"\\", tostring(EventData.SubjectUserName))
  | extend Activity= "1102 - The audit log was cleared."
  | summarize StartTimeUtc = min(TimeGenerated), EndTimeUtc = max(TimeGenerated), EventCount = count() by Computer, Account, EventID, Activity
  )
  )
  | extend Name=tostring(split(Account, "@")[0]), UPNSuffix=tostring(split(Account, "@")[1])
  | extend HostName = iif(Computer has '.',substring(Computer,0,indexof(Computer,'.')),Computer) , DnsDomain = iif(Computer has '.',substring(Computer,indexof(Computer,'.')+1),'')
entityMappings:
  - entityType: Account
    fieldMappings:
      - identifier: Name
        columnName: Name
      - identifier: UPNSuffix
        columnName: UPNSuffix
  - entityType: Host
    fieldMappings:
      - identifier: FullName
        columnName: Computer
      - identifier: HostName
        columnName: HostName
      - identifier: DnsDomain
        columnName: DnsDomain
version: 1.1.5
kind: Scheduled