Windows Event Log Cleared

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Description

The following analytic detects the clearing of Windows event logs by identifying Windows Security Event ID 1102 or System log event 104. This detection leverages Windows event logs to monitor for log clearing activities. Such behavior is significant as it may indicate an attempt to cover tracks after malicious activities. If confirmed malicious, this action could hinder forensic investigations and allow attackers to persist undetected, making it crucial to investigate further and correlate with other alerts and data sources.

• Type: TTP

• Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud

• Last Updated: 2024-07-24
• Author: Rico Valdez, Michael Haag, Splunk
• ID: ad517544-aff9-4c96-bd99-d6eb43bfbb6a

Annotations

ATT&CK

ATT&CK

ID	Technique	Tactic
T1070	Indicator Removal	Defense Evasion

T1070.001

Clear Windows Event Logs

Defense Evasion

Kill Chain Phase

• Exploitation

NIST

• DE.CM

CIS20

• CIS 10

CVE

Search

(`wineventlog_security` EventCode=1102) OR (`wineventlog_system` EventCode=104) 
| stats count min(_time) as firstTime max(_time) as lastTime by dest object EventCode 
| `security_content_ctime(firstTime)` 
| `security_content_ctime(lastTime)` 
| `windows_event_log_cleared_filter`

Macros

The SPL above uses the following Macros:

• security_content_ctime
• wineventlog_security
• wineventlog_system

windows_event_log_cleared_filter is a empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.

Required fields

List of fields required to use this analytic.

• _time
• EventCode
• dest

How To Implement

To successfully implement this search, you need to be ingesting Windows event logs from your hosts. In addition, the Splunk Windows TA is needed.

Known False Positives

It is possible that these logs may be legitimately cleared by Administrators. Filter as needed.

Associated Analytic Story

• Windows Log Manipulation
• Ransomware
• Clop Ransomware
• CISA AA22-264A
• ShrinkLocker

RBA

Risk Score	Impact	Confidence	Message
70.0	70	100	Windows $object$ cleared on $dest$ via EventCode $EventCode$

The Risk Score is calculated by the following formula: Risk Score = (Impact * Confidence/100). Initial Confidence and Impact is set by the analytic author.

Reference

• https://docs.microsoft.com/en-us/windows/security/threat-protection/auditing/event-1102
• https://www.ired.team/offensive-security/defense-evasion/disabling-windows-event-logs-by-suspending-eventlog-service-threads
• https://attack.mitre.org/techniques/T1070/001/
• https://github.com/redcanaryco/atomic-red-team/blob/master/atomics/T1070.001/T1070.001.md

Test Dataset

Replay any dataset to Splunk Enterprise by using our replay.py tool or the UI. Alternatively you can replay a dataset into a Splunk Attack Range

source | version: 9