Detection: Recursive Delete of Directory In Batch CMD

Updated Date: 2024-05-10 ID: ba570b3a-d356-11eb-8358-acde48001122 Author: Teoderick Contreras, Splunk Type: TTP Product: Splunk Enterprise Security

Description

The following analytic detects the execution of a batch command designed to recursively delete files or directories, a technique often used by ransomware like Reddot to delete files in the recycle bin and prevent recovery. It leverages data from Endpoint Detection and Response (EDR) agents, focusing on command-line executions that include specific flags for recursive and quiet deletions. This activity is significant as it indicates potential ransomware behavior aimed at data destruction. If confirmed malicious, it could lead to significant data loss and hinder recovery efforts, severely impacting business operations.

1
2| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Processes where `process_cmd` Processes.process=*/c*  Processes.process="* rd *"  Processes.process="*/s*" Processes.process="*/q*" by Processes.user Processes.process_name Processes.parent_process_name Processes.parent_process Processes.process Processes.process_id Processes.dest 
3|`drop_dm_object_name(Processes)` 
4| `security_content_ctime(firstTime)` 
5| `security_content_ctime(lastTime)` 
6| `recursive_delete_of_directory_in_batch_cmd_filter`

Data Source

Name Platform Sourcetype Source Supported App
CrowdStrike ProcessRollup2 N/A 'crowdstrike:events:sensor' 'crowdstrike' N/A

Macros Used

Name Value
process_cmd (Processes.process_name=cmd.exe OR Processes.original_file_name=Cmd.Exe)
recursive_delete_of_directory_in_batch_cmd_filter search *
recursive_delete_of_directory_in_batch_cmd_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
T1070.004 File Deletion Defense Evasion
T1070 Indicator Removal Defense Evasion
KillChainPhase.EXPLOITAITON
NistCategory.DE_CM
Cis18Value.CIS_10
APT18
APT28
APT29
APT3
APT32
APT38
APT39
APT41
APT5
Aquatic Panda
BRONZE BUTLER
Chimera
Cobalt Group
Dragonfly
Evilnum
FIN10
FIN5
FIN6
FIN8
Gamaredon Group
Group5
Kimsuky
Lazarus Group
Magic Hound
Metador
Mustang Panda
OilRig
Patchwork
Rocke
Sandworm Team
Silence
TeamTNT
The White Company
Threat Group-3390
Tropic Trooper
Volt Typhoon
Wizard Spider
menuPass
APT5
Lazarus Group

Default Configuration

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

Setting Value
Disabled true
Cron Schedule 0 * * * *
Earliest Time -70m@m
Latest Time -10m@m
Schedule Window auto
Creates Notable Yes
Rule Title %name%
Rule Description %description%
Notable Event Fields user, dest
Creates Risk Event True
This configuration file applies to all detections of type TTP. These detections will use Risk Based Alerting and generate Notable Events.

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

network operator may use this batch command to delete recursively a directory or files within directory

Associated Analytic Story

Risk Based Analytics (RBA)

Risk Message Risk Score Impact Confidence
Recursive Delete of Directory In Batch CMD by $user$ on $dest$ 25 50 50
The Risk Score is calculated by the following formula: Risk Score = (Impact * Confidence/100). Initial Confidence and Impact is set by the analytic author.

References

Detection Testing

Test Type Status Dataset Source Sourcetype
Validation ✅ Passing N/A N/A N/A
Unit ✅ Passing Dataset XmlWinEventLog:Microsoft-Windows-Sysmon/Operational xmlwineventlog
Integration ✅ Passing Dataset XmlWinEventLog:Microsoft-Windows-Sysmon/Operational xmlwineventlog

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: 4