Techniques
Sample rules
Windows InstallUtil Uninstall Option
- source: splunk
- technicques:
- T1218.004
- T1218
Description
The following analytic identifies the Windows InstallUtil.exe binary. This will execute code while bypassing application control using the /u (uninstall) switch.
InstallUtil uses the functions install and uninstall within the System.Configuration.Install namespace to process .net assembly. Install function requires admin privileges, however, uninstall function can be run as an unprivileged user.
When InstallUtil.exe is used in a malicous manner, the path to an executable on the filesystem is typically specified. Take note of the parent process. In a suspicious instance, this will be spawned from a non-standard process like Cmd.exe, PowerShell.exe or Explorer.exe.
If used by a developer, typically this will be found with multiple command-line switches/arguments and spawn from Visual Studio.
During triage review resulting network connections, file modifications, and parallel processes. Capture any artifacts and review further.
Detection logic
| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Processes where `process_installutil` Processes.process IN ("*/u*", "*uninstall*") 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_installutil_uninstall_option_filter`