Clearing of forensic evidence from event logs using wevtutil

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Id	515d0bba-b297-4f83-8280-20ff7f27ecb1
Rulename	Clearing of forensic evidence from event logs using wevtutil
Description	This query checks for attempts to clear at least 10 log entries from event logs using wevtutil. Clearing event logs can be a sign of ransomware activity, as ransomware often attempts to cover its tracks by deleting logs.
Severity	High
Tactics	DefenseEvasion
Techniques	T1070
Required data connectors	MicrosoftThreatProtection
Kind	Scheduled
Query frequency	1d
Query period	1d
Trigger threshold	0
Trigger operator	gt
Source Uri	https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Microsoft Defender XDR/Analytic Rules/Ransomware/LogDeletionUsingWevtutil.yaml
Version	1.0.0
Arm template	515d0bba-b297-4f83-8280-20ff7f27ecb1.json

KQL

// Look for use of wevtutil to clear multiple logs
DeviceProcessEvents
| where ProcessCommandLine has "WEVTUTIL" and ProcessCommandLine has "CL"
| summarize LogClearCount = dcount(tostring(ProcessCommandLine)), ClearedLogList = make_set(ProcessCommandLine, 100000) by DeviceId, DeviceName, bin(TimeGenerated, 5m)
| where LogClearCount > 10
| extend HostName = iff(DeviceName has '.', substring(DeviceName, 0, indexof(DeviceName, '.')), DeviceName)
| extend DnsDomain = iff(DeviceName has '.', substring(DeviceName, indexof(DeviceName, '.') + 1), "")

YAML

triggerOperator: gt
queryFrequency: 1d
description: |
    This query checks for attempts to clear at least 10 log entries from event logs using wevtutil. Clearing event logs can be a sign of ransomware activity, as ransomware often attempts to cover its tracks by deleting logs.
status: Available
kind: Scheduled
triggerThreshold: 0
requiredDataConnectors:
- connectorId: MicrosoftThreatProtection
  dataTypes:
  - DeviceProcessEvents
version: 1.0.0
queryPeriod: 1d
name: Clearing of forensic evidence from event logs using wevtutil
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Microsoft Defender XDR/Analytic Rules/Ransomware/LogDeletionUsingWevtutil.yaml
id: 515d0bba-b297-4f83-8280-20ff7f27ecb1
tactics:
- DefenseEvasion
relevantTechniques:
- T1070
severity: High
entityMappings:
- fieldMappings:
  - identifier: FullName
    columnName: DeviceName
  - identifier: HostName
    columnName: HostName
  - identifier: DnsDomain
    columnName: DnsDomain
  entityType: Host
query: |
  // Look for use of wevtutil to clear multiple logs
  DeviceProcessEvents
  | where ProcessCommandLine has "WEVTUTIL" and ProcessCommandLine has "CL"
  | summarize LogClearCount = dcount(tostring(ProcessCommandLine)), ClearedLogList = make_set(ProcessCommandLine, 100000) by DeviceId, DeviceName, bin(TimeGenerated, 5m)
  | where LogClearCount > 10
  | extend HostName = iff(DeviceName has '.', substring(DeviceName, 0, indexof(DeviceName, '.')), DeviceName)
  | extend DnsDomain = iff(DeviceName has '.', substring(DeviceName, indexof(DeviceName, '.') + 1), "")

ARM

{
  "$schema": "https://schema.management.azure.com/schemas/2019-04-01/deploymentTemplate.json#",
  "contentVersion": "1.0.0.0",
  "parameters": {
    "workspace": {
      "type": "String"
    }
  },
  "resources": [
    {
      "apiVersion": "2023-02-01-preview",
      "id": "[concat(resourceId('Microsoft.OperationalInsights/workspaces/providers', parameters('workspace'), 'Microsoft.SecurityInsights'),'/alertRules/515d0bba-b297-4f83-8280-20ff7f27ecb1')]",
      "kind": "Scheduled",
      "name": "[concat(parameters('workspace'),'/Microsoft.SecurityInsights/515d0bba-b297-4f83-8280-20ff7f27ecb1')]",
      "properties": {
        "alertRuleTemplateName": "515d0bba-b297-4f83-8280-20ff7f27ecb1",
        "customDetails": null,
        "description": "This query checks for attempts to clear at least 10 log entries from event logs using wevtutil. Clearing event logs can be a sign of ransomware activity, as ransomware often attempts to cover its tracks by deleting logs.\n",
        "displayName": "Clearing of forensic evidence from event logs using wevtutil",
        "enabled": true,
        "entityMappings": [
          {
            "entityType": "Host",
            "fieldMappings": [
              {
                "columnName": "DeviceName",
                "identifier": "FullName"
              },
              {
                "columnName": "HostName",
                "identifier": "HostName"
              },
              {
                "columnName": "DnsDomain",
                "identifier": "DnsDomain"
              }
            ]
          }
        ],
        "OriginalUri": "https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Microsoft Defender XDR/Analytic Rules/Ransomware/LogDeletionUsingWevtutil.yaml",
        "query": "// Look for use of wevtutil to clear multiple logs\nDeviceProcessEvents\n| where ProcessCommandLine has \"WEVTUTIL\" and ProcessCommandLine has \"CL\"\n| summarize LogClearCount = dcount(tostring(ProcessCommandLine)), ClearedLogList = make_set(ProcessCommandLine, 100000) by DeviceId, DeviceName, bin(TimeGenerated, 5m)\n| where LogClearCount > 10\n| extend HostName = iff(DeviceName has '.', substring(DeviceName, 0, indexof(DeviceName, '.')), DeviceName)\n| extend DnsDomain = iff(DeviceName has '.', substring(DeviceName, indexof(DeviceName, '.') + 1), \"\")\n",
        "queryFrequency": "P1D",
        "queryPeriod": "P1D",
        "severity": "High",
        "status": "Available",
        "suppressionDuration": "PT1H",
        "suppressionEnabled": false,
        "tactics": [
          "DefenseEvasion"
        ],
        "techniques": [
          "T1070"
        ],
        "templateVersion": "1.0.0",
        "triggerOperator": "GreaterThan",
        "triggerThreshold": 0
      },
      "type": "Microsoft.OperationalInsights/workspaces/providers/alertRules"
    }
  ]
}