Trojan horse Downloader.Generic.ML

Discussion in 'Computer Security' started by Ron Reaugh, Jun 15, 2005.

  1. Ron Reaugh

    kurt wismer Guest

    these days a threat can go from theoretical to 'practical' in a matter
    of minutes...

    and there have already been data diddlers in the past so i really don't
    think it's too unlikely that there will be more in the future...
    integrity master is an integrity checker with anti-viral applications...
    it does (did) have a few small features specific to virus detection,
    but they are not the primary features of the software...

    you may not like the way integrity master was designed, but it's not
    your product and the developer doesn't answer to you...
    not "should", "would"... and you described exactly that condition above
    with "if all that I could use was Stiller's Integrity Master"... that's
    an entirely arbitrary and artificial circumstance...

    but perhaps this is yet another point at which we diverge - as you seem
    to think a producer should try to provide all the parts to the virus
    prevention puzzle instead of just doing one thing really well... some of
    us actually think mixing and matching to get the best performance out of
    the various technologies available is a good strategy...

    i'm not demanding anything... you described what you could (or rather
    couldn't) do, i described what i could do
    it's sophistication for the masses to only care about what the
    anti-virus media machine tells them to care about? or is it the
    anti-virus media machine itself that represents the non-existent
    and corporations are somehow magically easier to dupe into believing the
    sophos propaganda? sorry, but corporations are run by the same sorts
    of people that are in the consumer market, they make their decisions in
    much the same ways except that they choose between corporate products
    instead of home-user products (usually)... the waving of hands and
    saying they stuck to the corporate market doesn't explain *why* people
    choose them over the alternatives when the alternatives offer something
    they don't...

    yours is the only definition i've seen that requires the original host's
    functionality be left intact... why i, or anyone else, should choose to
    use your definition over that of, say fred cohen, is beyond me (except
    from a producer's point of view i suppose it makes the virus problem
    statement easier to cope with when the definition of virus is changed to
    exclude the problem areas)...
    kurt wismer, Jun 27, 2005
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  2. Ron Reaugh

    Zvi Netiv Guest

    You repeated that nonsense so many times that you seem believing it yourself.
    Check IM's home page at and see its anti virus nature all over
    the place.

    Now you are plagiarizing me. ;-)

    Obviously, you haven't seen everything yet. ;) Besides, the definition I
    brought isn't mine and it doesn't contradict F. Cohen's.

    Regards, Zvi
    Zvi Netiv, Jun 28, 2005
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  3. Ron Reaugh

    kurt wismer Guest

    the website plays up the anti-virus application of the software because
    that's what distinguishes it from all the tools whose sole purpose is to
    check for corruption...
    his informal definition does not require that the original functionality
    of the host be maintained, and his formal definition states that all
    self-replicating programs are viruses... neither of these agree with the
    assertion you've put forward that viruses must maintain the original
    functionality of the host program...
    kurt wismer, Jun 29, 2005
  4. Ron Reaugh

    Roger Wilco Guest

    Maybe not a contradiction since he makes no mention one way or the
    other. But it wasn't omitted 'out of hand' it was omitted because it
    doesn't matter whether or not host function is maintained. The only part
    the host must play is that attempts to execute the host execute the
    virus. The definition you use puts further constraints on the virus and
    you sort of contradict what is inplied by Cohen's definition where he
    saw fit to omit any mention of host function being retained.

    In an arena of recovering files after having been infected by a virus I
    would like to use the same definition as you - any complaints about not
    being able to recover some files could be countered by "that was done by
    a trojan, not a virus - see my definition of virus" <URL>. :))
    Roger Wilco, Jun 29, 2005
  5. Ron Reaugh

    James Egan Guest

    As an aside, I happened across an article about this same
    vulnerability in ms word and excel.

    All versions of a (password protected) saved document use the same
    initialization vector so if you get hold of two different versions of
    the same document or a document which has been "saved as .." then
    subsequently edited and xor them against each other, you can read a
    portion of the output with winhex (or whatever). I just did a test
    with ms word 2k and could read more or less the complete text but
    apparently it applies to all versions of word and excel which use rc4.

    James Egan, Jun 30, 2005
  6. Ron Reaugh

    Zvi Netiv Guest

    Cohen's definition of virus: "A program that can 'infect' other programs by
    modifying them to include a possibly evolved version of itself".

    The definition I use expands on what is implied in the above. Nothing was
    omitted, nor added.

    Regards, Zvi
    Zvi Netiv, Jun 30, 2005
  7. Ron Reaugh

    Roger Wilco Guest

    The above implies nothing about the host's function still being intact.
    The 'inclusion' of something in a set does not imply that something else
    was not excluded - neither does it imply that it wasn't. You added that
    original host function must be retained in the resulting infected
    program thus further constraining the set of what you will call a virus.
    Roger Wilco, Jun 30, 2005
  8. Ron Reaugh

    Zvi Netiv Guest

    The subject was discussed at length in the thread below, in which you took part.

    I see no new arguments worth discussing.

    Regards, Zvi
    Zvi Netiv, Jul 2, 2005
  9. Ron Reaugh

    kurt wismer Guest

    kurt wismer, Jul 2, 2005
  10. Ron Reaugh

    Roger Wilco Guest

    With your obvious grasp of technical material it just surprised me that
    you use this as a definition for virus. Ay least this time I don't feel
    so all alone in my reluctance to agree with it. In any future
    discussions about viruses we'll just have to keep in mind that you use a
    rather unique definition.
    Roger Wilco, Jul 2, 2005
  11. Ron Reaugh

    Zvi Netiv Guest

    I first used that definition in my presentation (and paper) to the NCSA
    Conference of '91, in front of almost everyone in the field, at that date. I
    don't remember any objection to my interpreted definition from the audience, not
    then, nor later on, in endless discussions on generics vs classic AV. On the
    contrary. Quite a few adopted my interpretation and based similar features upon
    (Thunderbyte, Symantec, BRM - Fifth Generation, Eliashim).
    From you it almost sounds like being excommunicated. ;-)

    Regards, Zvi
    Zvi Netiv, Jul 3, 2005
  12. Ron Reaugh

    Roger Wilco Guest

    And yet the paper I quoted the definition from was titled "EICAR 2000
    Best Paper Proceedings" and the author saw fit to explicitly state that
    host functionality was not an issue instead of simply omitting any
    mention of it. Probably to avoid another misinterpretation such as you
    exhibit. In our previous discussion you also seemed to have
    misinterpreted something about first generation viruses - just because
    they are deemed not worthy of inclusion in test beds for AV comparatives
    does not mean they fail to meet the definition of virus. Sure, some
    can't be treated the same in the AV arena because they are not
    "infected" per se but they do meet the definition. You were correct
    about them being "best treated" as trojans - but that doesn't make them
    trojans and not viruses.
    Not so bad really - it's not like we're ever likely to to need to
    discuss thoses viruses that don't preserve host functionality since most
    of them do. But if one fails to achieve this in some spreading attempts
    it (the corrupted host with added viable viral code) should still be
    considerd a virus if the attempted execution of the host results in
    execution of the virus code.
    Roger Wilco, Jul 5, 2005
  13. Ron Reaugh

    Zvi Netiv Guest

    Our previous discussion was about whether overwriters should be considered
    viruses or not. Gen 1 samples were introduced to the discussion from Bontchev's
    paper on how to maintain a virus collection. I have no particular position in
    regard of these samples. You may consider them as valid viruses according to
    the definition, including my stringent one. Gen1 are actually a "do nothing"
    executable to which the virus code was added. The only difference between a
    gen1 file and a real infection is that the latter was created by a spontaneous
    infection process, and the previous was created artificially, through
    compilation. Note that spontaneity isn't required anywhere in the definition of
    You are confusing between droppers and genuine first generation virus samples.
    Do you have a difficulty admitting that they all do? ;-) Taking it one step
    further, can you formulate in words what that implies? Could it be that
    preserving the host functionality is inherent to "virus" conduct? It's called
    the scientific method, if you didn't know. ;)
    If it systematically corrupts rather than infect, then it's not a virus. If it
    exhibits irregular behavior, e.g. some instances fail to infect while others
    succeed, then it's a buggy virus, and if the botched infection resumes normal
    viral behavior when being executed, then it's a singularity and it's unimportant
    what you call it.

    Regards, Zvi
    Zvi Netiv, Jul 7, 2005
  14. Ron Reaugh

    Roger Wilco Guest

    Specifically those overwriters that don't retain host functionaltiy. I
    say that they should still be considered viruses because they still fit
    the definition(s) - except for yours :))
    IIRC you compared overwriters to the first generation viruses because
    you felt that the overwriters were essentially first generation viruses
    on each iteration - and hence are more akin to trojans than viruses.
    Detectors don't generally find this sort of thing when they are geared
    specifically to recognize "infected" files of the type that your
    definition indicates, so I can see why you would want to exclude them
    via your definition.
    I suppose so, considering what you say below.
    Since there was no functionality to be preserved in what is now the host
    "file" your definition works well enough. :)

    Even droppers are viruses if they create a copy of the viral code they
    'contain' in another executable area.

    Maybe I 'do' need some clarification of the terms "seed file", "germ
    file", and "dropper file". But it seems to me that any of them would be
    viruses if they contained the viral code and their execution resulted in
    that code being replicated into another program. AV may well be best
    applied to subsequent iterations (spontaneous infection process), but
    changing the definition of virus so that failing to cover them is not
    akin to failing to detect a "virus" only serves to confuse.
    A batch file (.bat) that overwrites other batch files with itself does
    exist - so I would have difficulty ignoring that fact. Without added
    "host funtionality retention" programming it would not be a very
    sophisticated virus, but it is still a virus.
    One could argue that other "virus conduct" such as avoiding multiple
    infections of the same program should be included in a definition. Just
    because it is a great advantage to have that conduct does not mean that
    conduct should become a part of the definition.
    It is bad science to ignore existing things just because they aren't
    often seen.

    If the corruption prevents the execution of the viral code, then it is
    not a virus. If the corruption only negatively affects the original host
    programs functionality and yet still correctly executes the viral code,
    then it 'is' a virus.

    Incidently, it is also not a virus (TM) if it corrupts the parent and
    only produces one offspring. Kurt mentioned in an earlier thread that he
    doesn't think this "non-overlapping" requirement was entirely
    necessary - but in a CA program (Life) you could have "sliders' that
    repositioned themselves (one unit diagonally?) and that would differ
    from a somewhat richer CA that replicated itself to another area of the
    2D tape without the new position overlapping the old position.
    Some programmatically and intentionally (the writers intention) exhibit
    such behavior to make emulation based detection more problematic.
    Something being "buggy" implies it was not what the author intended.

    Or do you have a unique definition for "buggy" as well. :))
    Interesting, could you explain this more? It seems that "botched
    infection" implies that it isn't a viable offspring and yet you say
    execution yields viral behavior which seems to indicate it 'was' viable.
    Is it this 'host functionality retention' that is "botched" in your
    above statement? If so, the "infection" wasn't botched - only the
    attempt to retain host functionality was botched. So I would call it a
    virus because I don't use your definition of virus.
    Roger Wilco, Jul 7, 2005
  15. Ron Reaugh

    kurt wismer Guest

    people generally do have difficulty admitting that which they know to be
    the scientific method calls for needlessly injecting further constraints
    into existing definitions?
    it is only by your definition that corruption of the host and infection
    are mutually exclusive... the real world is rarely so black and white...
    kurt wismer, Jul 8, 2005
  16. Ron Reaugh

    Zvi Netiv Guest

    Sorry, but I don't find it interesting to discuss that subject again.

    Regards, Zvi
    Zvi Netiv, Jul 9, 2005
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