LoFP LoFP / although unlikely, some legitimate applications (ex. web browsers) may spawn a child process. filter as needed.

Techniques

Sample rules

Detect HTML Help Spawn Child Process

Description

The following analytic detects the execution of hh.exe (HTML Help) spawning a child process, indicating the use of a Compiled HTML Help (CHM) file to execute Windows script code. This detection leverages data from Endpoint Detection and Response (EDR) agents, focusing on process creation events where hh.exe is the parent process. This activity is significant as it may indicate an attempt to execute malicious scripts via CHM files, a known technique for bypassing security controls. If confirmed malicious, this could lead to unauthorized code execution, potentially compromising the system.

Detection logic


| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Processes where Processes.parent_process_name=hh.exe by Processes.dest Processes.user Processes.parent_process_name Processes.parent_process 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)` 
| `detect_html_help_spawn_child_process_filter`