NRT Security Event log cleared

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Id	508cef41-2cd8-4d40-a519-b04826a9085f
Rulename	NRT 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
Tactics	DefenseEvasion
Techniques	T1070
Required data connectors	SecurityEvents WindowsSecurityEvents
Kind	NRT
Source Uri	https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Windows Security Events/Analytic Rules/NRT_SecurityEventLogCleared.yaml
Version	1.0.1
Arm template	508cef41-2cd8-4d40-a519-b04826a9085f.json

KQL

SecurityEvent
| where EventID == 1102 and EventSourceName == "Microsoft-Windows-Eventlog"
| summarize StartTimeUtc = min(TimeGenerated), EndTimeUtc = max(TimeGenerated), EventCount = count() by Computer, Account, EventID, Activity
| extend HostName = tostring(split(Computer, ".")[0]), DomainIndex = toint(indexof(Computer, '.'))
| extend HostNameDomain = iff(DomainIndex != -1, substring(Computer, DomainIndex + 1), Computer)
| extend AccountName = tostring(split(Account, @'\')[1]), AccountNTDomain = tostring(split(Account, @'\')[0])

YAML

relevantTechniques:
- T1070
name: NRT Security Event log cleared
requiredDataConnectors:
- dataTypes:
  - SecurityEvent
  connectorId: SecurityEvents
- dataTypes:
  - SecurityEvent
  connectorId: WindowsSecurityEvents
entityMappings:
- fieldMappings:
  - identifier: FullName
    columnName: Account
  - identifier: Name
    columnName: AccountName
  - identifier: NTDomain
    columnName: AccountNTDomain
  entityType: Account
- fieldMappings:
  - identifier: FullName
    columnName: Computer
  - identifier: HostName
    columnName: HostName
  - identifier: DnsDomain
    columnName: HostNameDomain
  entityType: Host
query: |
  SecurityEvent
  | where EventID == 1102 and EventSourceName == "Microsoft-Windows-Eventlog"
  | summarize StartTimeUtc = min(TimeGenerated), EndTimeUtc = max(TimeGenerated), EventCount = count() by Computer, Account, EventID, Activity
  | extend HostName = tostring(split(Computer, ".")[0]), DomainIndex = toint(indexof(Computer, '.'))
  | extend HostNameDomain = iff(DomainIndex != -1, substring(Computer, DomainIndex + 1), Computer)
  | extend AccountName = tostring(split(Account, @'\')[1]), AccountNTDomain = tostring(split(Account, @'\')[0])  
id: 508cef41-2cd8-4d40-a519-b04826a9085f
tactics:
- DefenseEvasion
version: 1.0.1
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Windows Security Events/Analytic Rules/NRT_SecurityEventLogCleared.yaml
kind: NRT
severity: Medium
status: Available
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.'

ARM

{
  "$schema": "https://schema.management.azure.com/schemas/2019-04-01/deploymentTemplate.json#",
  "contentVersion": "1.0.0.0",
  "parameters": {
    "workspace": {
      "type": "String"
    }
  },
  "resources": [
    {
      "apiVersion": "2024-01-01-preview",
      "id": "[concat(resourceId('Microsoft.OperationalInsights/workspaces/providers', parameters('workspace'), 'Microsoft.SecurityInsights'),'/alertRules/508cef41-2cd8-4d40-a519-b04826a9085f')]",
      "kind": "NRT",
      "name": "[concat(parameters('workspace'),'/Microsoft.SecurityInsights/508cef41-2cd8-4d40-a519-b04826a9085f')]",
      "properties": {
        "alertRuleTemplateName": "508cef41-2cd8-4d40-a519-b04826a9085f",
        "customDetails": null,
        "description": "'Checks for event id 1102 which indicates the security event log was cleared.\nIt uses Event Source Name \"Microsoft-Windows-Eventlog\" to avoid generating false positives from other sources, like AD FS servers for instance.'\n",
        "displayName": "NRT Security Event log cleared",
        "enabled": true,
        "entityMappings": [
          {
            "entityType": "Account",
            "fieldMappings": [
              {
                "columnName": "Account",
                "identifier": "FullName"
              },
              {
                "columnName": "AccountName",
                "identifier": "Name"
              },
              {
                "columnName": "AccountNTDomain",
                "identifier": "NTDomain"
              }
            ]
          },
          {
            "entityType": "Host",
            "fieldMappings": [
              {
                "columnName": "Computer",
                "identifier": "FullName"
              },
              {
                "columnName": "HostName",
                "identifier": "HostName"
              },
              {
                "columnName": "HostNameDomain",
                "identifier": "DnsDomain"
              }
            ]
          }
        ],
        "OriginalUri": "https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Windows Security Events/Analytic Rules/NRT_SecurityEventLogCleared.yaml",
        "query": "SecurityEvent\n| where EventID == 1102 and EventSourceName == \"Microsoft-Windows-Eventlog\"\n| summarize StartTimeUtc = min(TimeGenerated), EndTimeUtc = max(TimeGenerated), EventCount = count() by Computer, Account, EventID, Activity\n| extend HostName = tostring(split(Computer, \".\")[0]), DomainIndex = toint(indexof(Computer, '.'))\n| extend HostNameDomain = iff(DomainIndex != -1, substring(Computer, DomainIndex + 1), Computer)\n| extend AccountName = tostring(split(Account, @'\\')[1]), AccountNTDomain = tostring(split(Account, @'\\')[0])\n",
        "severity": "Medium",
        "status": "Available",
        "subTechniques": [],
        "suppressionDuration": "PT1H",
        "suppressionEnabled": false,
        "tactics": [
          "DefenseEvasion"
        ],
        "techniques": [
          "T1070"
        ],
        "templateVersion": "1.0.1"
      },
      "type": "Microsoft.OperationalInsights/workspaces/providers/alertRules"
    }
  ]
}