Следующее работало для меня, основываясь на этой статье
Set objWSH = CreateObject("WScript.Shell")
'This actually returns all the User Variables, and you either loop through all, or simply print what you want
Set objUserVariables = objWSH.Environment("USER")
MsgBox(objUserVariables("TEMP"))
'This returns all the System Variables, and you either loop through all, or simply print what you want
Set objSystemVariables = objWSH.Environment("SYSTEM")
MsgBox(objSystemVariables("PATH"))