InsecurePowerShellHost is a .NET Core host process for InsecurePowerShell, a version of PowerShell Core with key security features removed.

InsecurePowershell is a fork of PowerShell Core v6.0.0, with key security features removed. InsecurePowerShell removes the following security features from PowerShell:

• AMSI - InsecurePowerShell does not submit any PowerShell code to the AMSI, even when there is an actively listening AntiMalware Provider.
• PowerShell Logging - InsecurePowerShell disables ScriptBlockLogging, Module Logging, and Transcription Logging. Even if they are enabled in Group Policy, these settings are ignored.
• LanguageModes - InsecurePowerShell always runs PowerShell code in FullLanguage mode. Attempting to set InsecurePowerShell to alternative LanguageModes, such as ConstrainedLanguage mode or RestrictedLanguage mode does not take any affect.
• ETW - InsecurePowerShell does not utilize ETW (Event Tracing for Windows).

More details are available here.