splunk-security_content/docs/_posts/2021-06-02-revil_common_exec_parameter.md

title, excerpt, categories, last_modified_at, toc, toc_label, tags

title	excerpt	categories	last_modified_at	toc	toc_label	tags
Revil Common Exec Parameter	User Execution	Endpoint	2021-06-02	true		User Execution Execution Splunk Enterprise Splunk Enterprise Security Splunk Cloud Endpoint

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Description

This analytic identifies suspicious commandline parameter that are commonly used by REVIL ransomware to encrypts the compromise machine.

• Type: TTP
• Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
• Datamodel: Endpoint- Datasource: Splunk Add-on for Sysmon
• Last Updated: 2021-06-02
• Author: Teoderick Contreras, Splunk
• ID: 85facebe-c382-11eb-9c3e-acde48001122

Annotations

ATT&CK

ID	Technique	Tactic
T1204	User Execution	Execution

Kill Chain Phase

• Exploitation

NIST

CIS20

CVE

Search

| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Processes where Processes.process = "* -nolan *" OR Processes.process = "* -nolocal *" OR Processes.process = "* -fast *" OR Processes.process = "* -full *" by Processes.process_name Processes.process Processes.parent_process_name Processes.parent_process Processes.dest Processes.user Processes.process_id Processes.process_guid 
| `drop_dm_object_name(Processes)` 
| `security_content_ctime(firstTime)` 
| `security_content_ctime(lastTime)` 
| `revil_common_exec_parameter_filter`

Macros

The SPL above uses the following Macros:

• security_content_ctime
• security_content_summariesonly

ℹ️ revil_common_exec_parameter_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.process_name
• Processes.process
• Processes.parent_process_name
• Processes.parent_process
• Processes.dest
• Processes.user
• Processes.process_id
• Processes.process_guid

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

third party tool may have same command line parameters as revil ransomware.

Associated Analytic story

• Ransomware
• Revil Ransomware

RBA

Risk Score	Impact	Confidence	Message
54.0	60	90	A process process_name with commandline process related to revil ransomware in host dest

ℹ️ 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

• https://krebsonsecurity.com/2021/05/a-closer-look-at-the-darkside-ransomware-gang/
• https://www.mcafee.com/blogs/other-blogs/mcafee-labs/mcafee-atr-analyzes-sodinokibi-aka-revil-ransomware-as-a-service-what-the-code-tells-us/

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/revil/inf1/windows-sysmon.log

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