dark angel's phunky virus writing guide .txt

黑客培训教程

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DISCLAIMER: The author hereby disclaims himself
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DEDICATION: This was written to make the lives
  of scum such as Patty Hoffman, John McAffee,
  and Ross Greenberg a living hell.
-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
OTHER STUFF:  Thanks go to The Shade of Sorrow,
  Demogorgon, and Orion Rouge on their comments
  (which I occasionally listened to!).   Thanks
  also to Hellraiser, who gave me an example of
  some virus source code (his own, of course).
-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-

Dark Angel's Phunky Virus Writing Guide
---- ------- ------ ----- ------- -----
Virii are  wondrous creations written for the sole purpose of spreading and
destroying the  systems of unsuspecting fools.  This eliminates the systems
of simpletons  who can't  tell that there is a problem when a 100 byte file
suddenly blossoms  into a  1,000 byte  file.   Duh.  These low-lifes do not
deserve to  exist, so  it is  our sacred duty to wipe their hard drives off
the face of the Earth.  It is a simple matter of speeding along survival of
the fittest.

Why did  I create  this guide?  After writing several virii, I have noticed
that virus  writers generally  learn how to write virii either on their own
or by  examining the  disassembled code  of  other  virii.    There  is  an
incredible lack  of information  on the  subject.   Even books published by
morons such as Burger are, at best, sketchy on how to create a virus.  This
guide will show you what it takes to write a virus and also will give you a
plethora of source code to include in your own virii.

Virus writing  is not  as hard  as you  might first  imagine.   To write an
effective virus,  however, you  *must*  know  assembly  language.    Short,
compact code  are hallmarks  of assembly  language and  these are desirable
characteristics of  virii.  However, it is *not* necessary to write in pure
assembly.   C may  also be  used, as  it allows almost total control of the
system while  generating relatively compact code (if you stay away from the
library functions).   However,  you still  must access  the interrupts,  so
assembly knowledge  is still  required.  However, it is still best to stick
with pure  assembly,  since  most  operations  are  more  easily  coded  in
assembly.  If you do not know assembly, I would recommend picking up a copy
of The Microsoft Macro Assembler Bible (Nabajyoti Barkakati, ISBN #: 0-672-
22659-6).   It is an easy-to-follow book covering assembly in great detail.
Also get yourself a copy of Undocumented DOS (Schulman, et al, ISBN #0-201-
57064-5), as it is very helpful.

The question  of which  compiler to  use arises  often.   I  suggest  using
Borland Turbo  Assembler and/or  Borland C++.   I  do not  have a  copy  of
Zortech C  (it was  too large  to download), but I would suspect that it is
also a good choice.  Stay away from Microsoft compilers, as they are not as
flexible nor as efficient as those of other vendors.

A few more items round out the list of tools helpful in constructing virii.
The latest version of Norton Utilities is one of the most powerful programs
available, and  is immeasurably  helpful.   MAKE SURE YOU HAVE A COPY!  You
can find  it on  any decent board.  It can be used during every step of the
process, from  the writing  to the testing.  A good debugger helps.  Memory
management  utilities   such  as   MAPMEM,  PMAP,   and  MARK/RELEASE,  are
invaluable, especially  when coding  TSR virii.   Sourcer,  the  commenting
disassembler, is  useful when  you wish  to examine the code of other virii
(this is a good place to get ideas/techniques for your virus).

Now that  you have  your tools,  you are  ready to  create a  work  of  art
designed to smash the systems of cretins.  There are three types of virii:

     1) Tiny virii (under 500 bytes) which are designed to be  undetectable
        due to their small size.   TINY  is  one  such  virus.    They  are
        generally very simple because their code length is so limited.
     2) Large  virii  (over 1,500 bytes)   which   are   designed   to   be
        undetectable because they cover their tracks very  well  (all  that
        code DOES have a use!).  The best example  of  this  is  the  Whale
        virus, which is perhaps the best 'Stealth' virus in existence.
     3) Other virii which are not designed to be hidden at all (the writers
        don't give  a  shit).    The  common  virus  is  like  this.    All
        overwriting virii are in this category.

You must  decide which  kind of  virus you wish to write.  I will mostly be
discussing  the  second  type  (Stealth  virii).    However,  many  of  the
techniques discribed  may be easily applied to the first type (tiny virii).
However, tiny  virii generally do not have many of the "features" of larger
virii, such  as  directory  traversal.    The  third  type  is  more  of  a
replicating trojan-type,  and will  warrant a  brief  (very,  very  brief!)
discussion later.

A virus may be divided into three parts: the replicator, the concealer, and
the bomb.   The  replicator part  controls the spread of the virus to other
files, the concealer keeps the virus from being detected, and the bomb only
executes when  the activation  conditions of the virus (more on that later)
are satisfied.

-=-=-=-=-=-=-=-
THE REPLICATOR
-=-=-=-=-=-=-=-
The job  of the  replicator is to spread the virus throughout the system of
the clod  who has caught the virus.  How does it do this without destroying
the file it infects?  The easiest type of replicator infects COM files.  It
first saves  the first  few bytes  of the  infected file.  It then copies a
small portion of its code to the beginning of the file, and the rest to the
end.

  +----------------+      +------------+
  | P1 | P2        |      | V1 | V2    |
  +----------------+      +------------+
 The uninfected file     The virus code

In the  diagram, P1 is part 1 of the file, P2 is part 2 of the file, and V1
and V2  are parts 1 and 2 of the virus.  Note that the size of P1 should be
the same  as the size of V1, but the size of P2 doesn't necessarily have to
be the  same size  as V2.   The  virus first  saves P1 and copies it to the
either 1)  the end  of the  file or 2) inside the code of the virus.  Let's
assume it copies the code to the end of the file.  The file now looks like:

  +---------------------+
  | P1 | P2        | P1 |
  +---------------------+

Then, the  virus copies  the first  part of  itself to the beginning of the
file.

  +---------------------+
  | V1 | P2        | P1 |
  +---------------------+

Finally, the virus copies the second part of itself to the end of the file.
The final, infected file looks like this:

  +-----------------------------+
  | V1 | P2        | P1 | V2    |
  +-----------------------------+

The question  is: What  the fuck  do V1 and V2 do?  V1 transfers control of
the program to V2.  The code to do this is simple.

     JMP FAR PTR Duh       ; Takes four bytes
Duh  DW  V2_Start          ; Takes two bytes

Duh is  a far pointer (Segment:Offset) pointing to the first instruction of
V2.   Note that  the value  of Duh must be changed to reflect the length of
the file  that is  infected.   For example,  if the  original size  of  the
program is  79 bytes,  Duh must  be changed  so  that  the  instruction  at
CS:[155h] is  executed.   The value of Duh is obtained by adding the length
of V1,  the original size of the infected file, and 256 (to account for the
PSP).  In this case, V1 = 6 and P1 + P2 = 79, so 6 + 79 + 256 = 341 decimal
(155 hex).

An alternate, albeit more difficult to understand, method follows:

     DB 1101001b              ; Code for JMP (2 byte-displacement)
Duh  DW V2_Start - OFFSET Duh ; 2 byte displacement

This inserts  the jump  offset directly  into the  code following  the jump
instruction.  You could also replace the second line with

     DW V2_Start - $

which accomplishes the same task.

V2 contains the rest of the code, i.e. the stuff that does everything else.
The last  part of  V2 copies  P1 over  V1 (in memory, not on disk) and then
transfers control  to the  beginning of the file (in memory).  The original
program will  then run happily as if nothing happened.  The code to do this
is also very simple.

     MOV SI, V2_START      ; V2_START is a LABEL marking where V2 starts
     SUB SI, V1_LENGTH     ; Go back to where P1 is stored
     MOV DI, 0100h         ; All COM files are loaded @ CS:[100h] in memory
     MOV CX, V1_LENGTH     ; Move CX bytes
     REP MOVSB             ; DS:[SI] -> ES:[DI]

     MOV DI, 0100h
     JMP DI

This code assumes that P1 is located just before V2, as in:

P1_Stored_Here:
     .
     .
     .
V2_Start:

It also  assumes ES  equals CS.  If these assumptions are false, change the
code accordingly.  Here is an example:

     PUSH CS               ; Store CS
     POP  ES               ;  and move it to ES
                           ; Note MOV ES, CS is not a valid instruction
     MOV SI, P1_START      ; Move from whereever P1 is stored
     MOV DI, 0100h         ;  to CS:[100h]
     MOV CX, V1_LENGTH
     REP MOVSB

     MOV DI, 0100h
     JMP DI

This code  first moves CS into ES and then sets the source pointer of MOVSB
to where  P1 is located.  Remember that this is all taking place in memory,
so you  need the  OFFSET of P1, not just the physical location in the file.
The offset  of P1  is 100h  higher than  the physical file location, as COM
files are loaded starting from CS:[100h].

So here's a summary of the parts of the virus and location labels:

V1_Start:
     JMP FAR PTR Duh
Duh  DW  V2_Start
V1_End:

P2_Start:
P2_End:

P1_Start:
  ; First part of the program stored here for future use
P1_End:

V2_Start: