Re: Buffer overflow in awk

From: Pavel Kankovsky (peakat_private)
Date: Sun Mar 17 2002 - 06:48:43 PST

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    On Fri, 15 Mar 2002, Kurt Seifried wrote:
    
    > So you are willing to guarentee to us that this awk bug will never be
    > exploitable by an attacker in any circumstance? Cool. Oh wait, that's
    > totally bogus.
    
    No. I can guarantee that a person who can pass arbitrary values to awk's
    -f option controls the account running such an instance of (GNU) awk
    without having to resort to the buffer overflow being discussed.
    
    Just try those two commands:
    
      echo 'BEGIN {system("command of your choice")}' > /tmp/blah
      awk -f blah
    
    Or this single command:
    
      echo 'BEGIN {system("command of your choice")}' | awk -f /dev/stdin
    
    Of course, the buffer overflow is a bug and it should be fixed.
    But it is not a real security hole because -f's parameter is a trusted 
    input channel.
    
    --Pavel Kankovsky aka Peak  [ Boycott Microsoft--http://www.vcnet.com/bms ]
    "Resistance is futile. Open your source code and prepare for assimilation."
    



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