Detection: Windows Hunting System Account Targeting Lsass

Description

The following analytic identifies processes attempting to access Lsass.exe, which may indicate credential dumping or applications needing credential access. It leverages Sysmon EventCode 10 to detect such activities by analyzing fields like TargetImage, GrantedAccess, and SourceImage. This behavior is significant as unauthorized access to Lsass.exe can lead to credential theft, posing a severe security risk. If confirmed malicious, attackers could gain access to sensitive credentials, potentially leading to privilege escalation and further compromise of the environment.

Search

1`sysmon` EventCode=10 TargetImage=*lsass.exe 
2| stats count min(_time) as firstTime max(_time) as lastTime by dest, TargetImage, GrantedAccess, SourceImage, SourceProcessId, SourceUser, TargetUser  
3| `security_content_ctime(firstTime)` 
4| `security_content_ctime(lastTime)` 
5| `windows_hunting_system_account_targeting_lsass_filter`

Data Source

Name	Platform	Sourcetype	Source
Sysmon EventID 10	Windows	'xmlwineventlog'	'XmlWinEventLog:Microsoft-Windows-Sysmon/Operational'

Macros Used

Annotations

Default Configuration

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

Implementation

To successfully implement this search, you need to be ingesting logs with the process name, parent process, and command-line executions from your endpoints. If you are using Sysmon, you must have at least version 6.0.4 of the Sysmon TA. Enabling EventCode 10 TargetProcess lsass.exe is required.

Known False Positives

False positives will occur based on GrantedAccess and SourceUser, filter based on source image as needed. Utilize this hunting analytic to tune out false positives in TTP or anomaly analytics.

Associated Analytic Story

• CISA AA23-347A

• Credential Dumping

References

• https://en.wikipedia.org/wiki/Local_Security_Authority_Subsystem_Service

• https://docs.microsoft.com/en-us/windows/win32/api/minidumpapiset/nf-minidumpapiset-minidumpwritedump

• https://cyberwardog.blogspot.com/2017/03/chronicles-of-threat-hunter-hunting-for_22.html

• https://raw.githubusercontent.com/PowerShellMafia/PowerSploit/master/Exfiltration/Invoke-Mimikatz.ps1

• https://docs.microsoft.com/en-us/windows/win32/procthread/process-security-and-access-rights?redirectedfrom=MSDN

Detection Testing

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: 5