The following analytic detects the creation of suspicious tasks on a remote Windows endpoint using the at.exe command with command-line arguments. This technique is commonly used by red teams and adversaries for lateral movement and remote code execution. The at.exe binary leverages the deprecated AT protocol, which may still work on previous versions of Windows. Attackers can enable this protocol on demand by modifying a system registry key. It is important to consider potential false positives. While administrators may create scheduled tasks on remote systems, this activity is typically limited to a small set of hosts or users.
Identifying the creation of scheduled tasks on remote endpoints is crucial for a Security Operations Center (SOC) because it indicates potential unauthorized activity or an attacker attempting to establish persistence or execute malicious code. The impact of a true positive can be significant, leading to unauthorized access, data theft, or other damaging outcomes. During triage, investigate the source and purpose of the scheduled task, inspect relevant on-disk artifacts, and analyze concurrent processes to identify the extent of the attack and take appropriate response actions.
- Type: TTP
- Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
- Datamodel: Endpoint
- Last Updated: 2021-11-11
- Author: Mauricio Velazco, Splunk
- ID: 4be54858-432f-11ec-8209-3e22fbd008af
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=at.exe OR Processes.original_file_name=at.exe) (Processes.process=*\\\\*) by Processes.dest Processes.user Processes.parent_process_name Processes.process_name Processes.process Processes.process_id Processes.parent_process_id | `drop_dm_object_name(Processes)` | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)` | `scheduled_task_creation_on_remote_endpoint_using_at_filter`
The SPL above uses the following Macros:
scheduled_task_creation_on_remote_endpoint_using_at_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
Administrators may create scheduled tasks on remote systems, but this activity is usually limited to a small set of hosts or users.
Associated Analytic Story
|54.0||90||60||A Windows Scheduled Task was created on a remote endpoint from $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.
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