Intrusion Detection Systems mailing list archives

Re: RE: detecting a sniffer remotely


From: robert_david_graham () yahoo com (Robert Graham)
Date: Thu, 14 Oct 1999 06:34:39 -0700 (PDT)



--- "Hunt, Charles" <chunt () ikon com> wrote:
have you tried l0pht's antisniff product?
---
Hi there,

I've tried to detect a sniffer (ethernet card in PROMISCOUS)
remotely whithout result.

Does anyone knows if it's possible to detect remotely a sniffing host
(specially whithout knowing its IP or MAC address.

AntiSniff has a small bag of tricks, but they are not very reliable -- it isn't
supposed to be. In the range of technologies, something like a packet filering
firewall is absolutely reliable, intrusion detection technology is somewhat
reliable, but detecting sniffers is very hit or miss. If it doesn't work, there
are a huge numbers of variables that would affect why.

Yes, it is possible detect a remotely sniffing host with knowing it's IP
address or MAC address. Send out a ping to an IP address, then sniff yourself
to see if anybody does a reverse lookup on it. That is one of the many tricks
in AntiSniff's bag-o-tricks, but of course lots of sniffers don't do
reverse-DNS lookups; some wait until a user actually does a protocol decode on
the contents, which may be months later.

You might consider the little "sniffer detection guide" at:
http://www.robertgraham.com/pubs/sniffing-faq.html#detect

=====
Robert Graham
"Anxiously awaiting the millenium so I can start programming
dates with 2-digits again."
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