Detection: Windows Event Log Cleared

Updated Date: 2024-07-24 ID: ad517544-aff9-4c96-bd99-d6eb43bfbb6a Author: Rico Valdez, Michael Haag, Splunk Type: TTP Product: Splunk Enterprise Security

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.

Search

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

Data Source

Name	Platform	Sourcetype	Source	Supported App
Windows Event Log Security 1102	Windows	`'xmlwineventlog'`	`'XmlWinEventLog:Security'`	N/A

Macros Used

Name	Value
security_content_ctime	`convert timeformat="%Y-%m-%dT%H:%M:%S" ctime($field$)`
windows_event_log_cleared_filter	`search *`

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

Annotations

- MITRE ATT&CK

+ Kill Chain Phases

+ NIST

+ CIS

- Threat Actors

ID	Technique	Tactic
T1070	Indicator Removal	Defense Evasion
T1070.001	Clear Windows Event Logs	Defense Evasion

KillChainPhase.EXPLOITAITON

NistCategory.DE_CM

Cis18Value.CIS_10

APT5

Lazarus Group

APT28

APT32

APT38

APT41

Chimera

Dragonfly

FIN5

FIN8

Indrik Spider

Default Configuration

This detection is configured by default in Splunk Enterprise Security to run with the following settings:

Setting	Value
Disabled	true
Cron Schedule	`0 * * * *`
Earliest Time	`-70m@m`
Latest Time	`-10m@m`
Schedule Window	`auto`
Creates Notable	Yes
Rule Title	`%name%`
Rule Description	`%description%`
Notable Event Fields	user, dest
Creates Risk Event	True

This configuration file applies to all detections of type TTP. These detections will use Risk Based Alerting and generate Notable Events.

Implementation

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

Risk Based Analytics (RBA)

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

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

References

Detection Testing

Test Type	Status	Dataset	Source	Sourcetype
Validation	✅ Passing	N/A	N/A	N/A
Unit	✅ Passing	Dataset	`XmlWinEventLog:Security`	`XmlWinEventLog`
Integration	✅ Passing	Dataset	`XmlWinEventLog:Security`	`XmlWinEventLog`

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: GitHub | Version: 9