Techniques
Sample rules
Windows MSIExec DLLRegisterServer
- source: splunk
- technicques:
- T1218.007
Description
The following analytic detects the execution of msiexec.exe with the /y switch parameter, which enables the loading of DLLRegisterServer. This detection leverages data from Endpoint Detection and Response (EDR) agents, focusing on process command-line arguments and parent-child process relationships. This activity is significant because it can indicate an attempt to register malicious DLLs, potentially leading to code execution or persistence on the system. If confirmed malicious, this could allow an attacker to execute arbitrary code, escalate privileges, or maintain persistence within the environment.
Detection logic
| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Processes where `process_msiexec` Processes.process IN ("*/y*", "*-y*") 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)`
| `windows_msiexec_dllregisterserver_filter`
Windows MSIExec Unregister DLLRegisterServer
- source: splunk
- technicques:
- T1218.007
Description
The following analytic detects the use of msiexec.exe with the /z switch parameter, which is used to unload DLLRegisterServer. This detection leverages data from Endpoint Detection and Response (EDR) agents, focusing on process execution logs, including command-line arguments. This activity is significant because unloading DLLRegisterServer can be indicative of an attempt to deregister a DLL, potentially disrupting legitimate services or hiding malicious activity. If confirmed malicious, this could allow an attacker to disable security controls, evade detection, or disrupt system functionality, leading to further compromise of the environment.
Detection logic
| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Processes where `process_msiexec` Processes.process IN ("*/z*", "*-z*") 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)`
| `windows_msiexec_unregister_dllregisterserver_filter`