LoFP LoFP / false positives may be present. filtering may be required before setting to alert.

Techniques

Sample rules

Windows NirSoft Utilities

Description

The following analytic identifies the execution of commonly used NirSoft utilities on Windows systems. It leverages data from Endpoint Detection and Response (EDR) agents, focusing on process execution details such as process name, parent process, and command-line arguments. This activity is significant for a SOC because NirSoft utilities, while legitimate, can be used by adversaries for malicious purposes like credential theft or system reconnaissance. If confirmed malicious, this activity could lead to unauthorized access, data exfiltration, or further system compromise.

Detection logic


| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time)
as lastTime FROM datamodel=Endpoint.Processes
by Processes.action Processes.dest Processes.original_file_name Processes.parent_process
   Processes.parent_process_exec Processes.parent_process_guid Processes.parent_process_id
   Processes.parent_process_name Processes.parent_process_path Processes.process
   Processes.process_exec Processes.process_guid Processes.process_hash Processes.process_id
   Processes.process_integrity_level Processes.process_name Processes.process_path
   Processes.user Processes.user_id Processes.vendor_product

| `drop_dm_object_name("Processes")`

| `security_content_ctime(firstTime)`

| `security_content_ctime(lastTime)`

| lookup update=true is_nirsoft_software filename as process_name OUTPUT nirsoftFile

| search nirsoftFile=true

| `windows_nirsoft_utilities_filter`