Detection: Windows Terminating Lsass Process

Updated Date: 2024-08-15 ID: 7ab3c319-a4e7-4211-9e8c-40a049d0dba6 Author: Teoderick Contreras, Splunk Type: Anomaly Product: Splunk Enterprise Security

Description

The following analytic detects a suspicious process attempting to terminate the Lsass.exe process. It leverages Sysmon EventCode 10 logs to identify processes granted PROCESS_TERMINATE access to Lsass.exe. This activity is significant because Lsass.exe is a critical process responsible for enforcing security policies and handling user credentials. If confirmed malicious, this behavior could indicate an attempt to perform credential dumping, privilege escalation, or evasion of security policies, potentially leading to unauthorized access and persistence within the environment.

1`sysmon` EventCode=10 TargetImage=*lsass.exe GrantedAccess = 0x1 
2| stats count min(_time) as firstTime max(_time) as lastTime by SourceImage, TargetImage, TargetProcessId, SourceProcessId, GrantedAccess CallTrace, dest 
3| rename dest as dest 
4| `security_content_ctime(firstTime)` 
5| `security_content_ctime(lastTime)` 
6| `windows_terminating_lsass_process_filter`

Data Source

Name Platform Sourcetype Source Supported App
Sysmon EventID 10 Windows icon Windows 'xmlwineventlog' 'XmlWinEventLog:Microsoft-Windows-Sysmon/Operational' N/A

Macros Used

Name Value
security_content_ctime convert timeformat="%Y-%m-%dT%H:%M:%S" ctime($field$)
windows_terminating_lsass_process_filter search *
windows_terminating_lsass_process_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
T1562.001 Disable or Modify Tools Defense Evasion
T1562 Impair Defenses Defense Evasion
KillChainPhase.EXPLOITAITON
NistCategory.DE_AE
Cis18Value.CIS_10
Aquatic Panda
BRONZE BUTLER
Ember Bear
FIN6
Gamaredon Group
Gorgon Group
Indrik Spider
Kimsuky
Lazarus Group
Magic Hound
MuddyWater
Putter Panda
Rocke
TA2541
TA505
TeamTNT
Turla
Wizard Spider
Magic Hound

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 Risk Event True
This configuration file applies to all detections of type anomaly. These detections will use Risk Based Alerting.

Implementation

This search requires Sysmon Logs and a Sysmon configuration, which includes EventCode 10 for lsass.exe. This search uses an input macro named sysmon. We strongly recommend that you specify your environment-specific configurations (index, source, sourcetype, etc.) for Windows Sysmon logs. Replace the macro definition with configurations for your Splunk environment. The search also uses a post-filter macro designed to filter out known false positives.

Known False Positives

unknown

Associated Analytic Story

Risk Based Analytics (RBA)

Risk Message Risk Score Impact Confidence
a process $SourceImage$ terminates Lsass process in $dest$ 64 80 80
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:Microsoft-Windows-Sysmon/Operational xmlwineventlog
Integration ✅ Passing Dataset XmlWinEventLog:Microsoft-Windows-Sysmon/Operational 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: 3