The following analytic detects the creation of suspicious scheduled tasks in Windows, specifically tasks created using schtasks.exe with the -create flag and an XML parameter in the command-line. This technique is commonly employed by threat actors, adversaries, and red teamers to establish persistence or achieve privilege escalation on targeted hosts. Notably, malware like Trickbot and Winter-Vivern have been observed using XML files to create scheduled tasks. Monitoring and investigating this activity is crucial to mitigate potential security risks. It is important to be aware that scripts or administrators may trigger this analytic, leading to potential false positives. To minimize false positives, adjust the filter based on the parent process or application.
When a true positive is detected, it suggests an attacker's attempt to gain persistence or execute additional malicious payloads, potentially resulting in data theft, ransomware, or other damaging outcomes. During triage, review the source of the scheduled task, the command to be executed, and capture any relevant on-disk artifacts. Analyze concurrent processes to identify the source of the attack. This analytic enables analysts to detect and respond to potential threats early, mitigating the associated risks effectively.
- Type: TTP
- Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
- Datamodel: Endpoint
- Last Updated: 2023-04-05
- Author: Teoderick Contreras, Splunk
- ID: 7e03b682-3965-4598-8e91-a60a40a3f7e4
Kill Chain Phase
- CIS 10
1 2 3 4 5 6 | 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=*create* Processes.process="* /xml *" by Processes.user Processes.parent_process_name Processes.parent_process Processes.process_name Processes.process Processes.process_guid Processes.process_id Processes.parent_process_guid Processes.dest | `drop_dm_object_name(Processes)` | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)` | `windows_scheduled_task_created_via_xml_filter`
The SPL above uses the following Macros:
windows_scheduled_task_created_via_xml_filter is a empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.
List of fields required to use this analytic.
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
It is possible scripts or administrators may trigger this analytic. Filter as needed based on parent process, application.
Associated Analytic Story
|49.0||70||70||A scheduled task process, $process_name$, with 'create' or 'delete' commands present in the command line.|
The Risk Score is calculated by the following formula: Risk Score = (Impact * Confidence/100). Initial Confidence and Impact is set by the analytic author.
source | version: 1