splunk-security_content/docs/_posts/2021-09-13-jscript_execution_using_cscript_app.md

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Jscript Execution Using Cscript App	Command and Scripting Interpreter , JavaScript	Endpoint	2021-09-13	true		Command and Scripting Interpreter JavaScript Execution Execution Splunk Enterprise Splunk Enterprise Security Splunk Cloud Endpoint

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Description

This search is to detect a execution of jscript using cscript process. Commonly when a user run jscript file it was executed by wscript.exe application. This technique was seen in FIN7 js implant to execute its malicious script using cscript process. This behavior is uncommon and a good artifacts to check further anomalies within the network

• Type: TTP
• Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
• Datamodel: Endpoint
• Last Updated: 2021-09-13
• Author: Teoderick Contreras, Splunk
• ID: 002f1e24-146e-11ec-a470-acde48001122

ATT&CK

ID	Technique	Tactic
T1059	Command and Scripting Interpreter	Execution

| T1059.007 | JavaScript | Execution |

Search

| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Processes where (Processes.parent_process_name = "cscript.exe" AND Processes.parent_process = "*//e:jscript*") OR (Processes.process_name = "cscript.exe" AND Processes.process = "*//e:jscript*") by Processes.parent_process_name Processes.parent_process Processes.process_name Processes.process_id Processes.process Processes.dest Processes.user 
| `drop_dm_object_name(Processes)` 
| `security_content_ctime(firstTime)` 
| `security_content_ctime(lastTime)` 
| `jscript_execution_using_cscript_app_filter`

Macros

The SPL above uses the following Macros:

• security_content_ctime
• security_content_summariesonly

Note that jscript_execution_using_cscript_app_filter is a empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.

Required field

• _time
• Processes.parent_process_name
• Processes.parent_process
• Processes.process_name
• Processes.process_id
• Processes.process
• Processes.dest
• Processes.user

How To Implement

To successfully implement this search, you need to be ingesting logs with the process name, parent process, and command-line 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

• FIN7
• Remcos

Kill Chain Phase

• Exploitation

RBA

Risk Score	Impact	Confidence	Message
49.0	70	70	Process name process_name with commandline process to execute jscript in dest

Reference

• https://www.fireeye.com/blog/threat-research/2018/08/fin7-pursuing-an-enigmatic-and-evasive-global-criminal-operation.html
• https://attack.mitre.org/groups/G0046/

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

• https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/malware/fin7/fin7_macro_js_1/sysmon.log

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