Re: Antivirus scanner DoS with zip archives

From: Ron DuFresne (dufresneat_private)
Date: Mon Jun 18 2001 - 10:59:37 PDT

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    On Mon, 18 Jun 2001, Michel Arboi wrote:
    
    	[snip]
    
    > 
    > Countermeasures?
    > I am not sure that those attacks work (I just tried on my personal AV
    > at home). However, I'd suggest to forbid archives inside archives (or
    > not more than 1 level?!), or limit the global number & size of the
    > files inside.
    > A simple way to reject such things could be to set a timeout on the
    > scanning operation. If it takes too long, the file, attachment, web
    > page, whatever, is just rejected.
    > 
    > I'd appreciate comments on this weird idea...
    > 
    
    
    How much ability to determine problems would be lost, if the scanner reads
    only chunks of the file at a time, perhaps a tad larger then sed's line at
    a time?
    
    
    Thanks,
    
    Ron DuFresne
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    "Cutting the space budget really restores my faith in humanity.  It
    eliminates dreams, goals, and ideals and lets us get straight to the
    business of hate, debauchery, and self-annihilation." -- Johnny Hart
    	***testing, only testing, and damn good at it too!***
    
    OK, so you're a Ph.D.  Just don't touch anything.
    



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