Techniques
Sample rules
Regsvr32 Silent and Install Param Dll Loading
- source: splunk
- technicques:
- T1218.010
Description
The following analytic detects the loading of a DLL using the regsvr32 application with the silent parameter and DLLInstall execution. It leverages data from Endpoint Detection and Response (EDR) agents, focusing on process command-line arguments and parent process details. This activity is significant as it is commonly used by RAT malware like Remcos and njRAT to load malicious DLLs on compromised machines. If confirmed malicious, this technique could allow attackers to execute arbitrary code, maintain persistence, and further compromise the system.
Detection logic
| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Processes where `process_regsvr32` AND Processes.process="*/i*" 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)`
| where match(process,"(?i)[\-
|\/][Ss]{1}")
| `regsvr32_silent_and_install_param_dll_loading_filter`