Adding more VBScript obfuscation techniques are not just fun but also useful. Previously, the accepted VBScript repro: https://github.com/DoctorLai/VBScript_Obfuscator has provided two obfuscation methods: the default Chr and the ROT47, today I have spent some time adding the BASE64 Obfuscator.

Here is how it looks like to obfuscate the original VBScript source:

msgbox "Hello, @justyy"

to the obfuscated source:

Function l(a): With CreateObject("Msxml2.DOMDocument").CreateElement("aux"): .DataType = "bin.base64": .Text = a: l = r(.NodeTypedValue): End With: End Function
Function r(b): With CreateObject("ADODB.Stream"): .Type = 1: .Open: .Write b: .Position = 0: .Type = 2: .CharSet = "utf-8": r = .ReadText: .Close:  End With: End function
Execute l("TXNnQm94ICJIZWxsbywgQGp1c3R5eSI=")

The github: https://github.com/DoctorLai/VBScript_Obfuscator/blob/master/vbs_obfuscator_base64.vbs
This commit: https://github.com/DoctorLai/VBScript_Obfuscator/commit/caa0591786e49b3933bd0b58040a17da66ff37f4#diff-7f7f2ac63e7c129755a085f80305f3f8

Core VBScript obfuscation function

The obfuscation process has been implemented in the following function:

Function Obfuscator(vbs)
    Dim s, F1, F2
    s = str_to_base64(vbs)
    F1 = "Function l(a): With CreateObject(" & Chr(34) & "Msxml2.DOMDocument" & Chr(34) & ").CreateElement(" & Chr(34) & "aux" & Chr(34) & "): .DataType = "& Chr(34) & "bin.base64"& Chr(34) & ": .Text = a: l = r(.NodeTypedValue): End With: End Function"
    F2 = "Function r(b): With CreateObject("& Chr(34) & "ADODB.Stream"& Chr(34) & "): .Type = 1: .Open: .Write b: .Position = 0: .Type = 2: .CharSet = "& Chr(34) & "utf-8"& Chr(34) & ": r = .ReadText: .Close:  End With: End function"
    Obfuscator = F1 & vbCrLf & F2 & vbCrLf & "Execute l(" & Chr(34) & (s)& Chr(34) &")" & vbCrLf 
End Function