Windows Scheduled Task with Highest Privileges
Description
The following analytic detects the creation of a new scheduled task with the highest execution privileges via Schtasks.exe. It leverages Endpoint Detection and Response (EDR) logs to monitor for specific command-line parameters ('/rl' and 'highest') in schtasks.exe executions. This activity is significant as it is commonly used in AsyncRAT attacks for persistence and privilege escalation. If confirmed malicious, this could allow an attacker to maintain persistent access and execute tasks with elevated privileges, potentially leading to unauthorized system access and data breaches.
- Type: TTP
- Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
- Datamodel: Endpoint
- Last Updated: 2024-05-20
- Author: Teoderick Contreras, Splunk
- ID: 2f15e1a4-0fc2-49dd-919e-cbbe60699218
Annotations
ATT&CK
Kill Chain Phase
- Installation
- Exploitation
NIST
- DE.CM
CIS20
- CIS 10
CVE
Search
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| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Processes where Processes.process_name = "schtasks.exe" Processes.process = "*/rl *" Processes.process = "* highest *" by Processes.process_name Processes.parent_process_name Processes.parent_process Processes.process Processes.process_guid Processes.dest Processes.user
| `drop_dm_object_name(Processes)`
| `security_content_ctime(firstTime)`
| `security_content_ctime(lastTime)`
| `windows_scheduled_task_with_highest_privileges_filter`
Macros
The SPL above uses the following Macros:
windows_scheduled_task_with_highest_privileges_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
- Processes.dest
- Processes.user
- Processes.parent_process_name
- Processes.parent_process
- Processes.original_file_name
- Processes.process_name
- Processes.process
- Processes.process_id
- Processes.parent_process_path
- Processes.process_path
- Processes.parent_process_id
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
False positives may arise from legitimate applications that create tasks to run as SYSTEM. Therefore, it's recommended to adjust filters based on parent process or modify the query to include world writable paths for restriction.
Associated Analytic Story
RBA
Risk Score | Impact | Confidence | Message |
---|---|---|---|
64.0 | 80 | 80 | a $process_name$ creating a schedule task $process$ with highest run level privilege in $dest$ |
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
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