WBAdmin Delete System Backups
Description
This search looks for flags passed to wbadmin.exe (Windows Backup Administrator Tool) that delete backup files. This is typically used by ransomware to prevent recovery.
- Type: TTP
- Product: Splunk Behavioral Analytics
- Datamodel: Endpoint_Processes
- Last Updated: 2021-12-07
- Author: Michael Haag, Splunk
- ID: 71efbf52-4dbb-4c00-a520-306aa546cbb7
Annotations
Kill Chain Phase
- Exploitation
NIST
- PR.AC
- PR.IP
CIS20
- CIS 8
CVE
Search
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| from read_ssa_enriched_events()
| eval timestamp=parse_long(ucast(map_get(input_event, "_time"), "string", null)), cmd_line=lower(ucast(map_get(input_event, "process"), "string", null)), process_name=lower(ucast(map_get(input_event, "process_name"), "string", null)), process_path=ucast(map_get(input_event, "process_path"), "string", null), parent_process_name=ucast(map_get(input_event, "parent_process_name"), "string", null), event_id=ucast(map_get(input_event, "event_id"), "string", null)
| where (cmd_line IS NOT NULL AND process_name IS NOT NULL)
| where process_name="wbadmin.exe"
| where like (cmd_line, "%delete%") OR like (cmd_line, "%catalog%") OR like (cmd_line, "%systemstatebackup%")
| eval start_time=timestamp, end_time=timestamp, entities=mvappend(ucast(map_get(input_event, "dest_user_id"), "string", null), ucast(map_get(input_event, "dest_device_id"), "string", null)), body=create_map(["event_id", event_id, "cmd_line", cmd_line, "process_name", process_name, "parent_process_name", parent_process_name, "process_path", process_path])
| into write_ssa_detected_events();
Macros
The SPL above uses the following Macros:
wbadmin_delete_system_backups_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
- dest_device_id
- process_name
- parent_process_name
- process_path
- dest_user_id
- process
- cmd_line
How To Implement
To successfully implement this search you need to be ingesting information on process that include the name of the process responsible for the changes from your endpoints into the Endpoint_Processess
datamodel.
Known False Positives
Administrators may modify the boot configuration.
Associated Analytic Story
RBA
Risk Score | Impact | Confidence | Message |
---|---|---|---|
15.0 | 30 | 50 | An instance of $parent_process_name$ spawning $process_name$ was identified on endpoint $dest_device_id$ by user $dest_user_id$ attempting to delete system backups. |
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://github.com/redcanaryco/atomic-red-team/blob/master/atomics/T1490/T1490.md
- https://thedfirreport.com/2020/10/08/ryuks-return/
- https://attack.mitre.org/techniques/T1490/
- https://docs.microsoft.com/en-us/windows-server/administration/windows-commands/wbadmin
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: 1