Resize ShadowStorage volume
Description
The following analytic identifies the resizing of shadow storage volumes, a technique used by ransomware like CLOP to prevent the recreation of shadow volumes. This detection leverages data from Endpoint Detection and Response (EDR) agents, focusing on command-line executions involving "vssadmin.exe" with parameters related to resizing shadow storage. This activity is significant as it indicates an attempt to hinder recovery efforts by manipulating shadow copies. If confirmed malicious, this could lead to successful ransomware deployment, making data recovery difficult and increasing the potential for data loss.
- Type: TTP
- Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
- Datamodel: Endpoint
- Last Updated: 2024-05-13
- Author: Teoderick Contreras
- ID: bc760ca6-8336-11eb-bcbb-acde48001122
Annotations
Kill Chain Phase
- Actions On Objectives
NIST
- DE.CM
CIS20
- CIS 10
CVE
Search
1
2
3
4
5
6
| tstats `security_content_summariesonly` values(Processes.process) as cmdline values(Processes.parent_process_name) as parent_process values(Processes.process_name) as process_name min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Processes where Processes.parent_process_name = "cmd.exe" OR Processes.parent_process_name = "powershell.exe" OR Processes.parent_process_name = "powershell_ise.exe" OR Processes.parent_process_name = "wmic.exe" Processes.process_name = "vssadmin.exe" Processes.process="*resize*" Processes.process="*shadowstorage*" Processes.process="*/maxsize*" by Processes.parent_process_name Processes.parent_process Processes.process_name Processes.process Processes.dest Processes.user Processes.process_id Processes.process_guid
| `drop_dm_object_name(Processes)`
| `security_content_ctime(firstTime)`
|`security_content_ctime(lastTime)`
| `resize_shadowstorage_volume_filter`
Macros
The SPL above uses the following Macros:
resize_shadowstorage_volume_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.
- Processes.process
- Processes.parent_process_name
- _time
- Processes.process_name
- Processes.parent_process
- Processes.dest
- Processes.user
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
network admin can resize the shadowstorage for valid purposes.
Associated Analytic Story
RBA
Risk Score | Impact | Confidence | Message |
---|---|---|---|
72.0 | 80 | 90 | A process $parent_process_name$ attempt to resize shadow copy with commandline $process$ in host $dest$ |
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://www.mandiant.com/resources/fin11-email-campaigns-precursor-for-ransomware-data-theft
- https://blog.virustotal.com/2020/11/keep-your-friends-close-keep-ransomware.html
- https://github.com/redcanaryco/atomic-red-team/blob/master/atomics/T1490/T1490.md
- https://redcanary.com/blog/blackbyte-ransomware/
- https://docs.microsoft.com/en-us/windows-server/administration/windows-commands/vssadmin-resize-shadowstorage
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: 2