Try in Splunk Security Cloud

Description

The following analytic identifies instances where Microsoft Excel spawns Windows Script Host processes (cscript.exe or wscript.exe). This behavior is detected using Endpoint Detection and Response (EDR) telemetry, focusing on process creation events where the parent process is excel.exe. This activity is significant because it is uncommon and often associated with malicious actions, such as spearphishing attacks. If confirmed malicious, this could allow an attacker to execute scripts, potentially leading to code execution, data exfiltration, or further system compromise. Immediate investigation and mitigation are recommended.

  • Type: TTP
  • Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
  • Datamodel: Endpoint
  • Last Updated: 2024-08-14
  • Author: Michael Haag, Splunk
  • ID: 57fe880a-9be3-11eb-9bf3-acde48001122

Annotations

ATT&CK

ATT&CK

ID Technique Tactic
T1003.002 Security Account Manager Credential Access
T1003 OS Credential Dumping Credential Access
Kill Chain Phase
  • Exploitation
NIST
  • DE.CM
CIS20
  • CIS 10
CVE 


1
2
3
4
5
6



| tstats `security_content_summariesonly` count values(Processes.process) min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Processes where Processes.parent_process_name="excel.exe" Processes.process_name IN ("cscript.exe", "wscript.exe")  by Processes.parent_process Processes.parent_process_name Processes.process_name Processes.user Processes.dest 
| `drop_dm_object_name("Processes")` 
| `security_content_ctime(firstTime)`
|`security_content_ctime(lastTime)` 
| `excel_spawning_windows_script_host_filter`

Macros

The SPL above uses the following Macros:

:information_source: excel_spawning_windows_script_host_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
  • process_name
  • process_id
  • parent_process_name
  • dest
  • user
  • parent_process_id

How To Implement

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 should be limited, but if any are present, filter as needed. In some instances, cscript.exe is used for legitimate business practices.

Associated Analytic Story

RBA

Risk Score Impact Confidence Message
80.0 80 100 An instance of $parent_process_name$ spawning $process_name$ was identified on endpoint $dest$ by user $user$, indicating potential suspicious macro execution.

: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: 4