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Re: [Full-disclosure] (TOOL) TAPiON (Polymorphic Decryptor Generator) Engine
From: Piotr Bania <bania.piotr () gmail com>
Date: Fri, 09 Sep 2005 22:19:25 +0200


>If you want some indepth on polymorphis I recomend you the 29a papers:

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

Piotr Bania - <bania.piotr () gmail com> - 0xCD, 0x19
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