|Tactic||Defense Evasion, Execution|
|Platform||Windows Server 2003, Windows Server 2008, Windows Server 2012, Windows XP, Windows 7, Windows 8, Windows Server 2003 R2, Windows Server 2008 R2, Windows Server 2012 R2, Windows Vista, Windows 8.1|
|Data Sources||Process monitoring, Process command-line parameters|
|Defense Bypassed||Process whitelisting|
InstallUtil is a command-line utility that allows for installation and uninstallation of resources by executing specific installer components specified in .NET binaries.1 InstallUtil is located in the .NET directory on a Windows system:
C:\Windows\Microsoft.NET\Framework\v<version>\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
InstallUtil may not be necessary within a given environment. Use application whitelisting configured to block execution of InstallUtil.exe if it is not required for a given system or network to prevent potential misuse by adversaries.
Use process monitoring to monitor the execution and arguments of InstallUtil.exe. Compare recent invocations of InstallUtil.exe with prior history of known good arguments and executed binaries to determine anomalous and potentially adversarial activity. Command arguments used before and after the InstallUtil.exe invocation may also be useful in determining the origin and purpose of the binary being executed.