Detection: Detect Mimikatz Via PowerShell And EventCode 4703

DEPRECATED DETECTION

This detection has been marked as deprecated by the Splunk Threat Research team. This means that it will no longer be maintained or supported. If you have any questions or concerns, please reach out to us at research@splunk.com.

Updated Date: 2024-08-15 ID: 98917be2-bfc8-475a-8618-a9bb06575188 Author: Rico Valdez, Splunk Type: TTP Product: Splunk Enterprise Security

Description

This search looks for PowerShell requesting privileges consistent with credential dumping. Deprecated, looks like things changed from a logging perspective.

1`wineventlog_security` signature_id=4703 Process_Name=*powershell.exe 
2| rex field=Message "Enabled Privileges:\s+(?<privs>\w+)\s+Disabled Privileges:" 
3| where privs="SeDebugPrivilege" 
4| stats count min(_time) as firstTime max(_time) as lastTime by dest, Process_Name, privs, Process_ID, Message 
5| rename privs as "Enabled Privilege" 
6| rename Process_Name as process 
7|  `security_content_ctime(firstTime)`
8| `security_content_ctime(lastTime)` 
9| `detect_mimikatz_via_powershell_and_eventcode_4703_filter`

Data Source

Name Platform Sourcetype Source Supported App
N/A N/A N/A N/A N/A

Macros Used

Name Value
security_content_ctime convert timeformat="%Y-%m-%dT%H:%M:%S" ctime($field$)
detect_mimikatz_via_powershell_and_eventcode_4703_filter search *
detect_mimikatz_via_powershell_and_eventcode_4703_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
T1003.001 LSASS Memory Credential Access
KillChainPhase.EXPLOITAITON
NistCategory.DE_CM
Cis18Value.CIS_10
APT1
APT28
APT3
APT32
APT33
APT39
APT41
APT5
Aquatic Panda
BRONZE BUTLER
Blue Mockingbird
Cleaver
Earth Lusca
FIN13
FIN6
FIN8
Fox Kitten
GALLIUM
HAFNIUM
Indrik Spider
Ke3chang
Kimsuky
Leafminer
Leviathan
Magic Hound
MuddyWater
OilRig
PLATINUM
Sandworm Team
Silence
Threat Group-3390
Volt Typhoon
Whitefly
Wizard 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

You must be ingesting Windows Security logs. You must also enable the account change auditing here: http://docs.splunk.com/Documentation/Splunk/7.0.2/Data/MonitorWindowseventlogdata. Additionally, this search requires you to enable your Group Management Audit Logs in your Local Windows Security Policy and to be ingesting those logs. More information on how to enable them can be found here: http://whatevernetworks.com/auditing-group-membership-changes-in-active-directory/. Finally, please make sure that the local administrator group name is "Administrators" to be able to look for the right group membership changes.

Known False Positives

The activity may be legitimate. PowerShell is often used by administrators to perform various tasks, and it's possible this event could be generated in those cases. In these cases, false positives should be fairly obvious and you may need to tweak the search to eliminate noise.

Associated Analytic Story

Risk Based Analytics (RBA)

Risk Message Risk Score Impact Confidence
tbd 25 50 50
The Risk Score is calculated by the following formula: Risk Score = (Impact * Confidence/100). Initial Confidence and Impact is set by the analytic author.

Detection Testing

Test Type Status Dataset Source Sourcetype
Validation Not Applicable N/A N/A N/A
Unit ❌ Failing N/A N/A N/A
Integration ❌ Failing N/A N/A N/A

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: 3