Re: FTP denial of service attack

From: Renaud Deraison (deraisonat_private)
Date: Tue Dec 07 1999 - 09:46:05 PST

  • Next message: Henrik Nordstrom: "Re: FTP denial of service attack"

    On Tue, 7 Dec 1999, Darren Reed wrote:
    
    > Who has more free file descriptors & network ports, you or the ftp server ?
    
    
    The attack you are describing is not new - this is just a PASV attack,
    which has been around for years.
    
    Hopefully, this problem is now solved.
    
    Most modern FTP servers will :
    
    	- either issue an error when they are issued a second
    	  PASV command
    
    	- either accept the new PASV command, but they will close
    	  the previously open socket, so the FTP server has only
    	  two fd's open at a time.
    
    If your FTP server server do not do this, use a real one.
    
    
    				-- Renaud
    
    
    --
    Renaud Deraison
    The Nessus Project - http://www.nessus.org
    



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