Techniques
Sample rules
Winhlp32 Spawning a Process
- source: splunk
- technicques:
- T1055
Description
The following analytic identifies winhlp32.exe, found natively in c:\windows\, spawning a child process that loads a file out of appdata, programdata, or temp. Winhlp32.exe has a rocky past in that multiple vulnerabilities were found and added to MetaSploit. WinHlp32.exe is required to display 32-bit Help files that have the “.hlp” file name extension. This particular instance is related to a Remcos sample where dynwrapx.dll is added to the registry under inprocserver32, and later module loaded by winhlp32.exe to spawn wscript.exe and load a vbs or file from disk. During triage, review parallel processes to identify further suspicious behavior. Review module loads for unsuspecting unsigned modules. Capture any file modifications and analyze.
Detection logic
| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Processes where Processes.parent_process_name=winhlp32.exe Processes.process IN ("*\\appdata\\*","*\\programdata\\*", "*\\temp\\*") by Processes.dest Processes.user Processes.parent_process_name Processes.process_name Processes.original_file_name Processes.process Processes.process_id Processes.parent_process_id
| `drop_dm_object_name(Processes)`
| `security_content_ctime(firstTime)`
| `security_content_ctime(lastTime)`
| `winhlp32_spawning_a_process_filter`