Detection: Windows System Binary Proxy Execution MSIExec Unregister DLL
Description
The following analytic identifies the usage of msiexec.exe using the /z switch parameter, which grants the ability for msiexec to unload DLLRegisterServer. Upon triage, review parent process and capture any artifacts for further review.
Annotations
No annotations available.
Implementation
To successfully implement this search, you need to be ingesting logs with the process name, parent process, and command-line executions from your endpoints. If you are using Sysmon, you must have at least version 6.0.4 of the Sysmon TA.
Known False Positives
False positives may be present, filter by destination or parent process as needed.
Associated Analytic Story
Risk Based Analytics (RBA)
| Risk Message | Risk Score | Impact | Confidence |
|---|---|---|---|
| An instance of spawning $process_file_name$ was identified on endpoint $device_hostname$ by user $actor_user_name$ attempting to unregister a DLL. | 35 | 70 | 50 |
The Risk Score is calculated by the following formula: Risk Score = (Impact * Confidence/100). Initial Confidence and Impact is set by the analytic author.
References
Version: 4