although unlikely, limited instances of regasm.exe or may cause a false positive. filter based endpoint usage, command line arguments, or process lineage.

Techniques

T1218.009

Sample rules

Detect Regasm with no Command Line Arguments

source: splunk
technicques:
- T1218.009

Description

The following analytic detects instances of regasm.exe running without command line arguments. This behavior typically indicates process injection, where another process manipulates regasm.exe. The detection leverages Endpoint Detection and Response (EDR) data, focusing on process names and command-line executions. This activity is significant as it may signal an attempt to evade detection or execute malicious code. If confirmed malicious, attackers could achieve code execution, potentially leading to privilege escalation, persistence, or access to sensitive information. Investigate network connections, parallel processes, and suspicious module loads for further context.

Detection logic


| tstats `security_content_summariesonly` count FROM datamodel=Endpoint.Processes where
(Processes.process_name=regasm.exe OR Processes.original_file_name=RegAsm.exe)
Processes.process IN ("*regasm","*regasm.exe", "*regasm.exe\"")
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)`

| `detect_regasm_with_no_command_line_arguments_filter`