From: bontchev@fbihh.informatik.uni-hamburg.de (Vesselin Bontchev)
Newsgroups: comp.virus
Subject: Re: Virus Simulator MtE Suppliment (PC)
Date: 5 Jan 93 18:39:30 GMT

as194@cleveland.Freenet.Edu (Doren Rosenthal) writes:

>  Thank  you for your comments on my Virus Simulator MtE Supplement. I'll  be 
>  mailing  the first copies january 1, so I hope your opinion  is  mistakenly 
>  based  on  my original Virus Simulator and not your technical review  of  a 
>  program you could not possibly have examined yet. Readers of this forum may 
>  recall  the  considerable  controversy and  strong  opinion  you  expressed 
>  beginning two weeks before my release of that program as well.

Well, Frisk's comments about your Virus Simulator turned out to be
right even after it appeared, so I would guess that he understands the
principles behind such "test" tools even better than you do...

>  pattern  to avoid recognition. A few examples of viruses that  employ  this 
>  same MtE engine are:
>  
>  Pogue,  Dame, MtE, Gotcha, 7S, Mut, Dedicated, Fear, Groove,  Coffee  Shop, 
>  MtE-Spawn, Questo, Crypto Lab, Encroach. 

Corrections: By "7S" you probably mean "Seventh_Son" ("7S" is how SCAN
calls it) and it is NOT based on MtE. "Dame" is not a virus, it is
just how SCAN call -all- MtE-based viruses. Gotcha is NOT an MtE-based
virus. Dunno what you are calling "Mut" but I know about no such
MtE-based virus. The CARO name for "MtE-Spawn" is "Insufficient". The
correct spelling of the last two names is "CryptLab" and "Encroacher".
"MtE" is not a virus; it is a tool for building polymorphic viruses.

When looking at the names you quoted, I am getting the impression that
you knowledge about the names of the existing MtE-based viruses is
based on the reports generated by SCAN, since it sometimes reports the
unencrypted variants of Pogue as "Gotcha" (which is correct - Pogue is
actually a Gotcha variant with MtE polymorphism added), and one of the
older versions of SCAN reported "7S" in some unencrypted variants of
one of the other MtE-based viruses (not certain about that; have to
check).

>  Although  the  MtE  simulations  produced  by  my  program  are  safe   and 
>  controlled, they are real viruses, capable of infecting their special dummy 
>  host  programs.

So, you are not only distributing malicious software (MtE) but also
real viruses, hmm? Anyway, Frisk's comment is still valid. The ability
of a scanner to detect "your" viruses may or may not be related to its
ability to detect -real- MtE-based viruses.

> Vigilant anti-virus programs that are capable  of  reliably 
>  detecting the MtE mutation engine should report these simulations as  being 
>  infected. 

Usually, yes, but not necessarily. It depends on how your viruses
infect their victims, how often they are generating unencrypted
replicants, how exactly the particular scanner works, and so on. As I
said, it may or it may not be connected with the actual ability of the
scanner to detect the existing MtE-based viruses... But if a scanner
- -doesn't- detect some of "your" viruses, this is a serious reason for
further investigation. It does not necessarily mean that that
particular scanner will also miss a real MtE-based virus, but it is
worth checking why it misses your virus...

Regards,
Vesselin
- -- 
Vesselin Vladimirov Bontchev          Virus Test Center, University of Hamburg
Tel.:+49-40-54715-224, Fax: +49-40-54715-226      Fachbereich Informatik - AGN
< PGP 2.1 public key available on request. > Vogt-Koelln-Strasse 30, rm. 107 C
e-mail: bontchev@fbihh.informatik.uni-hamburg.de    D-2000 Hamburg 54, Germany
Newsgroups: comp.programming