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Re: DoS in debian (potato) proftpd: 1.2.0pre10-2.0potato1



also sprach Alun Jones <alun@texis.com> [2002.04.04.0445 +0200]:
> >  DenyFilter \*.*/
> 
> Just as a quick question, why not deny the string "/../" (you may have to 
> deny the regex "/\.\./", depending how the filter in question works)?

quick answer: because i merely copied the fix from the security pages
of the proftpd homepage [1].

  1. http://proftpd.linux.co.uk/critbugs.html

> As far as I can tell, it's the ability to embed "/../" into a path that is 
> at the root of this, far more than the ability to embed wildcards.  I can't 
> think of a situation in which "/../" should appear in a user-supplied path, 
> except after a string of repeated "../"s.

i actually agree with you here.

> "[^/.].*/\.\./"

mh, this would not prevent

  /some/.dotdir/../

right?

-- 
martin;              (greetings from the heart of the sun.)
  \____ echo mailto: !#^."<*>"|tr "<*> mailto:"; net@madduck
  
to vacillate or not to vacillate,
that is the question ... or is it?

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