Clearing of forensic evidence from event logs using wevtutil

Back


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

relevantTechniques:
- T1070
entityMappings:
- fieldMappings:
  - columnName: DeviceName
    identifier: FullName
  - columnName: HostName
    identifier: HostName
  - columnName: DnsDomain
    identifier: DnsDomain
  entityType: Host
triggerThreshold: 0
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.
requiredDataConnectors:
- connectorId: MicrosoftThreatProtection
  dataTypes:
  - DeviceProcessEvents
triggerOperator: gt
version: 1.0.0
OriginalUri: https://github.com/Azure/Azure-Sentinel/blob/master/Solutions/Microsoft Defender XDR/Analytic Rules/Ransomware/LogDeletionUsingWevtutil.yaml
id: 515d0bba-b297-4f83-8280-20ff7f27ecb1
queryFrequency: 1d
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), "")  
severity: High
status: Available
queryPeriod: 1d
name: Clearing of forensic evidence from event logs using wevtutil
tactics:
- DefenseEvasion
kind: Scheduled

ARM