Re: [logs] Logging in the DMZ (fwd)

From: Raffael Marty (rmarty@private)
Date: Mon Feb 09 2004 - 16:19:27 PST

  • Next message: Tina Bird: "Re: [logs] Logging in the DMZ (fwd)"

    On Mon, 09 Feb 2004, Tina Bird wrote:
    
    > here's a broad overview:
    > 
    > http://www.linuxjournal.com/modules.php?op=modload&name=NS-lj-issues/issue92&file=5476s2
    > 
    > basically, you pick a "fake" IP address for the apparent address of the
    > DMZ logserver.  all boxes in the DMZ get a static ARP entry for a fake MAC
    > addr to go with the fake IP address.  then you put an interface with no IP
    > address in promiscuous mode and collect anything destined for UDP/514 on
    > the apparent loghost.
    > 
    > you can use tcpdump or snort or whatever you like to reassemble the syslog
    > data out of the packets.  i think JP vossen has info on how to use snort
    > for this on his web site, but i'm having trouble tracking it down
    > anywhere...
    
    If you do this, you might want to also use a one-way patch-cable that
    allows packets to only flow from the DMZ _to_ your log server. That way
    you don't even have to use a "fake" IP address for the log host. The
    advantage is that there is no way to compromise that system. [okay,
    there is, if someone would manage to exploit the syslog daemon and ... -
    let's not go there]. This is also the way you can setup your NIDS, just
    attach it to the same cable!
    
    Info about how to build such a one-way patch-cable you find on
    snort.org: http://www.snort.org/docs/tap/
    
    	-raffy
    
    -- 
    
    Raffael Marty, CISSP                          raffael.marty@private
    Senior Security Engineer                    Content Team @ ArcSight Inc.
    1309 South Mary Ave.         Sunnyvale, CA 94087          (408) 328 5562
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