Re: Ports 0-1023?

From: gminick (gminickat_private)
Date: Thu Jul 04 2002 - 02:35:00 PDT

  • Next message: Brian Hatch: "Re: Ports 0-1023?"

    On Thu, Jul 04, 2002 at 12:05:16AM -0700, Blue Boar wrote:
    > Is there any point in needing to be root in order to allocate the low ports 
    > on unix-like systems, anymore?
    It's a dangerous situation, when unpriviledged users are able
    to run fake-daemons on ports where there should work a root
    process or nothing. Imagine a situation, when on your server
    you run only sshd and some server such as MTA, http server, but
    there's a possibility of starting a process (some _malicious_ process) 
    on ports like 21/ftp, 23/telnet and getting passwords of your
    users (you do not need to create a working ftp server, you just
    need to get passwords and drop a connection with some error message,
    it's about 50 lines of code). It's rather not a good idea, to
    give such a possibility to all of your users.
    
    > Could some sort of port ACL 
    > simply be used that says a particular UID can allocate a particular range 
    > of ports?
    I don't know, but even if it isn't possible, it's not hard to 
    code it.
    
    -- 
    [ Wojtek gminick Walczak ][ http://hacker.pl/gminick/ ]
    [ gminick (at) hacker.pl ][ gminick (at) klub.chip.pl ]
    



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