while legitimate, these nirsoft tools are prone to abuse. you should verify that the tool was used for a legitimate purpose.

Techniques

T1072

Sample rules

Detection of tools built by NirSoft

source: splunk
technicques:
- T1072

Description

The following analytic identifies the execution of tools built by NirSoft by detecting specific command-line arguments such as “/stext” and “/scomma”. It leverages data from Endpoint Detection and Response (EDR) agents, focusing on process names, parent processes, and command-line executions. This activity is significant because NirSoft tools, while legitimate, can be exploited by attackers for malicious purposes such as credential theft or system reconnaissance. If confirmed malicious, this activity could lead to unauthorized access, data exfiltration, or further compromise of the affected system.

Detection logic


| tstats `security_content_summariesonly` count min(_time) values(Processes.process) as process max(_time) as lastTime FROM datamodel=Endpoint.Processes
  WHERE (
        Processes.process="* /stext *"
        OR
        Processes.process="* /scomma *"
    )
  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)`

| `detection_of_tools_built_by_nirsoft_filter`