[Full-disclosure] (TOOL) TAPiON (Polymorphic Decryptor Generator) Engine

Piotr Bania bania.piotr at gmail.com
Fri Sep 9 21:19:25 BST 2005


Re,

 >...
 >If you want some indepth on polymorphis I recomend you the 29a papers:
 >http://vx.netlux.org/29a/

I'm not a master in this branch however let me citate one of the 
aritcles found on the server you sent me (i also recomend you to read it):

----- CUT --------------------------------------------------------------
" There exists a system of division of polymorphic viruses into levels 
according to complexity of code in decryptors of those viruses. Such a 
system was introduced by Dr. Alan Solomon and then enhanced by Vesselin 
Bontchev.

     Level 1: Viruses having a set of decryptors with constant code, 
choosing one while infecting. Such viruses are called "semi-polymorphic" 
or "oligomor phic".

Examples: "Cheeba", "Slovakia", "Whale".

     Level 2: Virus decryptor contains one or several constant 
instructions, the rest of it is changeable.

     Level 3: decryptor contains unused functions - "junk" like NOP, 
CLI, STI,etc

     Level 4: decryptor uses interchangeable instructions and changes 
their order (instructions mixing). Decryption algorithm remains unchanged.

     Level 5: all the above mentioned techniques are used, decryption 
algorithm is changeable, repeated encryption of virus code and even 
partial encryption of the decryptor code is possible. "
----- CUT --------------------------------------------------------------


So appending to this source i got a level 3 or level 4, unless you fully 
understand the source. I'm not saying it is perfect, is was written in 5 
days.

Hope this helps you.


best regards,
Piotr Bania


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