Detection: Windows NirSoft Utilities

Updated Date: 2024-08-15 ID: 5b2f4596-7d4c-11ec-88a7-acde48001122 Author: Michael Haag, Splunk Type: Hunting Product: Splunk Enterprise Security

Description

The following analytic identifies the execution of commonly used NirSoft utilities on Windows systems. It leverages data from Endpoint Detection and Response (EDR) agents, focusing on process execution details such as process name, parent process, and command-line arguments. This activity is significant for a SOC because NirSoft utilities, while legitimate, can be used by adversaries for malicious purposes like credential theft or system reconnaissance. If confirmed malicious, this activity could lead to unauthorized access, data exfiltration, or further system compromise.

1
2| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime FROM datamodel=Endpoint.Processes by Processes.dest Processes.user Processes.parent_process_name Processes.process_name Processes.process Processes.original_file_name Processes.process_path Processes.process_id Processes.parent_process_id 
3| `drop_dm_object_name("Processes")` 
4| `security_content_ctime(firstTime)` 
5| `security_content_ctime(lastTime)` 
6| `is_nirsoft_software_macro` 
7| `windows_nirsoft_utilities_filter`

Data Source

Name Platform Sourcetype Source Supported App
CrowdStrike ProcessRollup2 N/A 'crowdstrike:events:sensor' 'crowdstrike' N/A

Macros Used

Name Value
is_nirsoft_software_macro `lookup update=true is_nirsoft_software filename as process_name OUTPUT nirsoftFile
windows_nirsoft_utilities_filter search *
windows_nirsoft_utilities_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
T1588.002 Tool Resource Development
KillChainPhase.WEAPONIZATION
NistCategory.DE_AE
Cis18Value.CIS_10
APT-C-36
APT1
APT19
APT28
APT29
APT32
APT33
APT38
APT39
APT41
Aoqin Dragon
Aquatic Panda
BITTER
BRONZE BUTLER
BackdoorDiplomacy
BlackTech
Blue Mockingbird
Carbanak
Chimera
Cinnamon Tempest
Cleaver
Cobalt Group
CopyKittens
DarkHydrus
DarkVishnya
Dragonfly
Earth Lusca
Ember Bear
FIN10
FIN13
FIN5
FIN6
FIN7
FIN8
Ferocious Kitten
GALLIUM
Gorgon Group
HEXANE
Inception
IndigoZebra
Ke3chang
Kimsuky
LAPSUS$
Lazarus Group
Leafminer
LuminousMoth
Magic Hound
Metador
Moses Staff
MuddyWater
POLONIUM
Patchwork
PittyTiger
Sandworm Team
Silence
Silent Librarian
TA2541
TA505
Threat Group-3390
Thrip
Turla
Volt Typhoon
WIRTE
Whitefly
Wizard Spider
menuPass

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 False
This configuration file applies to all detections of type hunting.

Implementation

The detection is based on data that originates from Endpoint Detection and Response (EDR) agents. These agents are designed to provide security-related telemetry from the endpoints where the agent is installed. To implement this search, you must ingest logs that contain the process GUID, process name, and parent process. Additionally, you must ingest complete command-line executions. These logs must be processed using the appropriate Splunk Technology Add-ons that are specific to the EDR product. The logs must also be mapped to the Processes node of the Endpoint data model. Use the Splunk Common Information Model (CIM) to normalize the field names and speed up the data modeling process.

Known False Positives

False positives may be present. Filtering may be required before setting to alert.

Associated Analytic Story

Risk Based Analytics (RBA)

Risk Message Risk Score Impact Confidence
An instance of $parent_process_name$ spawning $process_name$ was identified on endpoint $dest$ by user $user$ related to NiRSoft software usage. 80 80 100
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: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