Previously, the very basic VBScript obfuscator has been accepted by utopian. However, the obfuscated source code is lengthy, which is made up by chr functions.

Today, I have added another VBScript obfuscator using the rot47 technique. Here is How it looks like for original un-obfuscated VBScript source:

MsgBox "Hello, @justyy"

And after obfuscation, here is the version that protects itself from an easy glance.

Function l(str):Dim i,j,k,r:j=Len(str):r="":For i=1 to j:k=Asc(Mid(str,i,1)):If k>=33 And k<=126 Then:r=r&Chr(33+((k+14)Mod 94)):Else:r=r&Chr(k):End If:Next:l=r:End Function
Execute l("|D8q@I Qw6==@[ o;FDEJJQ")

Similar to previous obfuscator, you can obfuscate the VBS via the command line, for example:

cscript.exe vbs_rot47_obfuscator.vbs sample.vbs > sample-obfuscated.vbs

How it works?

The ROT47 is a Caesar cipher by 47 chars. If you apply rot47 on the same string twice, you will get its original version:

Function Rot47(str)
    Dim i, j, k, r
    j = Len(str)
    r = ""
    For i = 1 to j
        k = Asc(Mid(str, i, 1))
        If k >= 33 And k <= 126 Then
            r = r & Chr(33 + ((k + 14) Mod 94))
        Else
            r = r & Chr(k)
        End If
    Next
    Rot47 = r
End Function
Function Obfuscator(vbs)
    Dim length, s, i, F
    F = "Function l(str):Dim i,j,k,r:j=Len(str):r=" & Chr(34) & Chr(34) & ":For i=1 to j:k=Asc(Mid(str,i,1)):If k>=33 And k<=126 Then:r=r&Chr(33+((k+14)Mod 94)):Else:r=r&Chr(k):End If:Next:l=r:End Function"
    length = Len(vbs)
    s = ""
    For i = 1 To length
        s = s & Rot47(Mid(vbs, i, 1))
    Next    
    Obfuscator = F & vbCrlf & "Execute l(" & Chr(34) & (s)& Chr(34) &")" & vbCrLf 
End Function

Github: https://github.com/DoctorLai/VBScript_Obfuscator
This commit: https://github.com/DoctorLai/VBScript_Obfuscator/commit/3465706f2e27b159a4a8769ca644fdb0a62de963#diff-eee917fa686f483d877fc2b1d9e7e886

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Posted on Utopian.io - Rewarding Open Source Contributors

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