Detection: Sdelete Application Execution

Updated Date: 2024-05-23 ID: 31702fc0-2682-11ec-85c3-acde48001122 Author: Teoderick Contreras, Splunk Type: TTP Product: Splunk Enterprise Security

Description

The following analytic detects the execution of the sdelete.exe application, a Sysinternals tool often used by adversaries to securely delete files and remove forensic evidence from a targeted host. This detection leverages data from Endpoint Detection and Response (EDR) agents, focusing on process execution logs. Monitoring this activity is crucial as sdelete.exe is not commonly used in regular operations and its presence may indicate an attempt to cover malicious activities. If confirmed malicious, this could lead to the loss of critical forensic data, hindering incident response and investigation efforts.

1
2| tstats `security_content_summariesonly` values(Processes.process) as process values(Processes.parent_process) as parent_process values(Processes.process_id) as process_id count min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Processes where `process_sdelete` by  Processes.process_name Processes.original_file_name Processes.dest Processes.user Processes.parent_process_name Processes.parent_process 
3| `drop_dm_object_name(Processes)` 
4| `security_content_ctime(firstTime)` 
5| `security_content_ctime(lastTime)` 
6| `sdelete_application_execution_filter`

Data Source

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

Macros Used

Name Value
process_sdelete (Processes.process_name=sdelete.exe OR Processes.original_file_name=sdelete.exe)
sdelete_application_execution_filter search *
sdelete_application_execution_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
T1485 Data Destruction Impact
T1070.004 File Deletion Defense Evasion
T1070 Indicator Removal Defense Evasion
KillChainPhase.ACTIONS_ON_OBJECTIVES
KillChainPhase.EXPLOITAITON
NistCategory.DE_CM
Cis18Value.CIS_10
APT38
Gamaredon Group
LAPSUS$
Lazarus Group
Sandworm Team
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

user may execute and use this application

Associated Analytic Story

Risk Based Analytics (RBA)

Risk Message Risk Score Impact Confidence
sdelete process $process_name$ executed in $dest$ 49 70 70
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: 2