T1118.md

T1118 - InstallUtil

Description from ATT&CK

InstallUtil is a command-line utility that allows for installation and uninstallation of resources by executing specific installer components specified in .NET binaries. (Citation: MSDN InstallUtil) InstallUtil is located in the .NET directories on a Windows system: C:\Windows\Microsoft.NET\Framework\v\InstallUtil.exe and C:\Windows\Microsoft.NET\Framework64\v\InstallUtil.exe. InstallUtil.exe is digitally signed by Microsoft.

Adversaries may use InstallUtil to proxy execution of code through a trusted Windows utility. InstallUtil may also be used to bypass process whitelisting through use of attributes within the binary that execute the class decorated with the attribute [System.ComponentModel.RunInstaller(true)]. (Citation: LOLBAS Installutil)

Atomic Tests

• Atomic Test #1 - InstallUtil uninstall method call

• Atomic Test #2 - InstallUtil GetHelp method call

Atomic Test #1 - InstallUtil uninstall method call

Executes the Uninstall Method

Supported Platforms: Windows

Inputs

Name	Description	Type	Default Value
filename	location of the payload	Path	C:\AtomicRedTeam\atomics\T1118\src\T1118.dll

Run it with command_prompt!

C:\Windows\Microsoft.NET\Framework\v4.0.30319\csc.exe /target:library /out:C:\AtomicRedTeam\atomics\T1118\src\T1118.dll C:\AtomicRedTeam\atomics\T1118\src\T1118.cs 
C:\Windows\Microsoft.NET\Framework\v4.0.30319\InstallUtil.exe /logfile= /LogToConsole=false /U #{filename}

Atomic Test #2 - InstallUtil GetHelp method call

Executes the Uninstall Method

Supported Platforms: Windows

Inputs

Name	Description	Type	Default Value
filename	location of the payload	Path	C:\AtomicRedTeam\atomics\T1118\src\T1118.dll

Run it with command_prompt!

C:\Windows\Microsoft.NET\Framework\v4.0.30319\csc.exe /target:library /out:C:\AtomicRedTeam\atomics\T1118\src\T1118.dll C:\AtomicRedTeam\atomics\T1118\src\T1118.cs 
C:\Windows\Microsoft.NET\Framework\v4.0.30319\InstallUtil.exe /? #{filename}