Try in Splunk Security Cloud

Description

This analytic identifies potentially malicious 'ImageLoaded' events, particularly when they involve executable files. This behavior was observed in NjRAT instances, where, during each instance of loading a module from its C2 server onto the compromised host, Sysmon recorded the path of the actual Image or Process as an 'ImageLoaded' event, rather than the typical tracking of dynamically loaded DLL modules in memory. This event holds significance because it tracks processes that load modules and libraries, which are typically in the .dll format rather than .exe. Leveraging this 'Time-To-Perform' (TTP) detection method can prove invaluable for the identification of NjRAT malware or other malicious software instances that introduce executable files as modules within a targeted host.

  • Type: TTP

  • Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud

  • Last Updated: 2023-09-12
  • Author: Teoderick Contreras, Splunk
  • ID: 3e27af56-fcf0-4113-988d-24969b062be7

Annotations

ATT&CK

ATT&CK

ID Technique Tactic
T1129 Shared Modules Execution
Kill Chain Phase
  • Installation
NIST
  • DE.CM
CIS20
  • CIS 10
CVE 


1
2
3
4
5
6



`sysmon` EventCode=7 ImageLoaded= *.exe 
| stats count min(_time) as firstTime max(_time) as lastTime by Image ImageLoaded Signed SignatureStatus OriginalFileName process_name Computer EventCode ProcessId Hashes IMPHASH 
| rename Computer as dest 
| `security_content_ctime(firstTime)` 
| `security_content_ctime(lastTime)` 
| `windows_executable_in_loaded_modules_filter`

Macros

The SPL above uses the following Macros:

:information_source: windows_executable_in_loaded_modules_filter is a empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.

Required fields

List of fields required to use this analytic.

  • _time
  • Image
  • ImageLoaded
  • Signed
  • SignatureStatus
  • OriginalFileName
  • process_name
  • Computer
  • EventCode
  • ProcessId
  • Hashes
  • IMPHASH

How To Implement

To successfully implement this search, you need to be ingesting logs with the process name and imageloaded executions from your endpoints. If you are using Sysmon, you must have at least version 6.0.4 of the Sysmon TA.

Known False Positives

unknown.

Associated Analytic Story

RBA

Risk Score Impact Confidence Message
64.0 80 80 An executable $Imageloaded$ loaded by $Image$ on $dest$

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

Reference

Test Dataset

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 | version: 1