Bugtraq mailing list archives

Re: Hidden sniffer on unplumb'ed interface on Solaris


From: "Chris St. Clair" <chris_stclair () HOTMAIL COM>
Date: Mon, 8 Jan 2001 16:28:39 -0000

After reading the following article
(http://www.enteract.com/~robt/Docs/Howto/Sun/sniffer-trick.txt) by >Rob
Thomas, it was brought to my attention that a sniffer can be >silently
sitting on an unplumb'ed interface on Solaris. Not only is >this dangerous
for large networks, it is often hard to find. Has >anyone ever contacted
Sun about this potential problem...I'm fixing >to try this on Solaris 8 to
determine if the problem still exists.

True, this could be a very bad thing. But you can do this with almost
any OS and platform; worst case cut the transmit wires of the cable
you're sniffing from.

We've done this for quite some time with our IDS engines, and it has
worked out very nicely. The interface is tremendously difficult to
detect, but still sniffs very reliably.

However, after reading Rob's paper I revisited the way I configure
my stealth interfaces in Solaris 2.6 and found it was quite different.

Using a null /etc/hostname.hme1 file:
/usr/sbin/ifconfig hme1 plumb -arp up

By bringing the interface up in this manner (actually plumb'ing it
but not assigning it an address) you get the added functionality of
being able to send forged packets out of it if you need to.

-chris
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