Re: Automated IDS response

From: Michael H. Warfield (mhwat_private)
Date: Sat Feb 12 2000 - 10:38:15 PST

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    On Fri, Feb 11, 2000 at 10:12:40AM -0500, Kopf , Patrick E. wrote:
    > Network Ice's BlackIce Defender IDS does this type of traffic blocking
    > (based on type of attack).  Defender only blocks traffic for attacks that
    > are 'non-spoofable'.  I don't know if they're the only IDS that does this or
    > not.
    
    	Portsentry <www.psionic.com> does this for Unix/Linux systems
    as well.  You can select what classes of services it will react to.  I
    don't advice UDP or "stealth TCP" because it's spoofable, but connected
    TCP port scans works great.
    
    	Doesn't have content reaction capability though.  Shutting down
    a route based on CGI script activity would be a bit much.
    
    	Sorry...  Not a Windows product.  Works great on a Linux firewall
    protecting the Windows boxen behind the firewall if you are on a cable
    modem or an xDSL connection.  :-)
    
    > Pat Kopf
    
    > -----Original Message-----
    > From: Michael B. Rash [mailto:mbrat_private]
    > Sent: Thursday, February 10, 2000 6:09 PM
    > To: firewall-wizardsat_private
    > Subject: Automated IDS response
    > 
    > 
    > 
    > Having your IDS respond automatically to an IP that is generating
    > questionable traffic by dynamically managing your router ACLs (or other
    > similar action; tcpwrappers, ipchains, etc...) to deny all traffic from
    > the IP can be a risky thing to do from a DoS perspective; nmap's decoy
    > option comes to mind.
    > 
    > It would seem that any IDS should only block traffic from an IP
    > based on an attack signature that requires bi-directional communication,
    > like a CGI exploit over http/80 or something.  Are there guidelines for
    > deploying IDS response that discusses methods for minimizing false
    > positives?  Are there any *good* ways of doing this?
    > 
    > --Mike
    > http://www.math.umd.edu/~mbr
    
    -- 
     Michael H. Warfield    |  (770) 985-6132   |  mhwat_private
      (The Mad Wizard)      |  (770) 331-2437   |  http://www.wittsend.com/mhw/
      NIC whois:  MHW9      |  An optimist believes we live in the best of all
     PGP Key: 0xDF1DD471    |  possible worlds.  A pessimist is sure of it!
    



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