Detection: Excel Spawning Windows Script Host

REMOVED DETECTION

This detection has been removed from the Splunk Threat Research content library and is no longer maintained or supported.

Reason: Detection deprecated as it no longer effectively identifies the intended malicious activity

Removed in version: 5.2.0

If you have any questions or concerns, please reach out to us at research@splunk.com.

Description

The following analytic has been deprecated in favour of a more generic approach. 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.

1
2| 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 
3| `drop_dm_object_name("Processes")` 
4| `security_content_ctime(firstTime)`
5|`security_content_ctime(lastTime)` 
6| `excel_spawning_windows_script_host_filter`

Data Source

Name Platform Sourcetype Source
Sysmon EventID 1 Windows icon Windows 'XmlWinEventLog' 'XmlWinEventLog:Microsoft-Windows-Sysmon/Operational'
Windows Event Log Security 4688 Windows icon Windows 'XmlWinEventLog' 'XmlWinEventLog:Security'
CrowdStrike ProcessRollup2 Other 'crowdstrike:events:sensor' 'crowdstrike'

Macros Used

Name Value
security_content_summariesonly summariesonly=summariesonly_config allow_old_summaries=oldsummaries_config fillnull_value=fillnull_config``
excel_spawning_windows_script_host_filter ``
excel_spawning_windows_script_host_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
T1003.002 Security Account Manager Credential Access

Default Configuration

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

Setting Value
Disabled true
Cron Schedule N/A
Earliest Time N/A
Latest Time N/A
Schedule Window N/A
Creates Finding (Notable) No
Creates Intermediate Finding (Risk Event) No
TTP detections generate a Finding (Notable) and may generate Intermediate Findings (Risk Events) for associated entities.

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 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

References

Detection Testing

Test Type Status Dataset Source Sourcetype
Validation Not Applicable N/A N/A N/A
Unit Not Applicable N/A N/A N/A
Integration Not Applicable N/A N/A N/A

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: 10