last ↗

Use the last() function to retrieve the last chronologically recorded value of a specified field within a grouped set of records.

Syntax

last (<field>)

Parameters

Name Type Required Description
field any Yes The field from which to extract the last recorded value based on chronological order.

Returns

The last() function returns the value of the specified field from the newest (most recent) event in the evaluated group. The data type of the returned value matches the data type of the input field.

Usage Notes

  • The last() function is an aggregate function and must be used within the comp stage.
  • The chronological order of the records is determined by the underlying time field (such as _time) associated with the data events.
  • If the last record contains a NULL value for the evaluated field, the function returns NULL.
  • This function is frequently used in threat hunting to identify the most recent occurrence of an artifact or behavior, such as the final command executed in a session, the last known IP address for a host, or the most recent process started by a specific user.

Examples

Example 1: Identify the last process executed per host

Goal: Find the most recently recorded process name that was executed on each endpoint within the queried time frame.

XQL Code:

config timeframe = 1d  
| dataset = xdr_data  
| filter action_process_image_name \!= null  
| comp last(action_process_image_name) as last_process by agent_hostname  
| fields agent_hostname, last_process  
| limit 3

Explanation: The comp stage groups the events by agent_hostname. For each unique host, the last() function evaluates the timeline of the records and returns the action_process_image_name associated with the chronologically newest event in that group. The result is assigned to the last_process alias.

Output:

AGENT_HOSTNAME LAST_PROCESS
endpoint-win-01 C:\Windows\System32\cmd.exe
endpoint-mac-02 /usr/libexec/xpcproxy
srv-linux-03 /bin/bash

Example 2: Retrieve the last command line for a process

Goal: Identify the final command line argument used to execute a specific process across your environment before the query timeframe ended.

XQL Code:

config timeframe = 1d  
| dataset = xdr_data  
| filter action_process_image_name = "powershell.exe"  
| comp last(action_process_image_command_line) as final_cmd by agent_hostname  
| fields agent_hostname, final_cmd  
| limit 2

Explanation: This query filters for execution events involving powershell.exe. Using the comp stage, it groups the results by agent_hostname and uses the last() function to extract the chronologically final command line argument executed by PowerShell on that host.

Output:

AGENT_HOSTNAME FINAL_CMD
endpoint-win-01 powershell.exe -WindowStyle Hidden -EncodedCommand JABz...
srv-win-02 "C:\Windows\System32\WindowsPowerShell\v1.0\powershell.exe" -c "Get-Process"