How to Detect Process Injection of PowerShell Backdoor with Native CMD or Powershell commands ?

I'm doing a cyber training exercise and believe red team has a powershell backdoor on a box we're investigating . The box does not have any extra installed software such as sysinternals its just a basic windows image . This has lead me to wondering if there is a good way to detect process injection such as DLL hijacking or PE injection with native commands . Links to any resources or scripts is greatly appreciated .

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