Wireshark mailing list archives

Re: Wireshark in Network - Windows/Linux


From: Hobbe <my1listmail () gmail com>
Date: Tue, 16 Mar 2010 11:07:04 +0100

Hi
None of them supports detecting a sniffer, they all detect that the network
card is in promiscous mode.
That a network card is in promiscous mode only means that there is a chance
of that machine could be used as a sniffer, but it is not the same as it is
a sniffer device.

To find sniffers and such you would have to run a software inventory program
that checks out what software does exist in the machines.
Then you can say: "ok we have found sniffer software on the machines".

The different tools do different things so do a search for them and se wich
one/ones would help you find out what you want.

HTH
Hobbe


2010/3/16 Karthik Balaguru <karthikbalaguru79 () gmail com>

On Sun, Mar 14, 2010 at 4:45 PM, Hobbe <my1listmail () gmail com> wrote:
As far as i know there is no way to detect a sniffer in a network,
however
there are some ways that can detect network cards in promiscuous mode,
tools
for this could be antisniff, neped, promgryui, sniffer-detect and so on.
They all do NOT detect a sniffer "per se", they detect that a network
card
is in promiscuous mode wich is a strong indicator that there is a
sniffer.

Thx for your reply.
antisniff, neped, promgryui, sniffer-detect - Do they support
detection of sniffer
in both windows and linux ? Thought of checking it with you before actually
going in for analyzing those. Any ideas ?

This does not however show the sniffers used with SPAN or RSPAN ports in
switches since those ports are shutdown for outgoing traffic from the
sniffer and only mirrors the traffic on the ports choosen.

HTH
Hobbe

2010/3/13 Karthik Balaguru <karthikbalaguru79 () gmail com>

On Wed, Mar 10, 2010 at 12:03 AM, Guy Harris <guy () alum mit edu> wrote:

On Mar 9, 2010, at 8:35 AM, Karthik Balaguru wrote:

How to determine the presence of wireshark in a network ? Are there
any specific packet types exchanged while it is present in the
network
so that it can be used to determine its presence in the network ? Any
specific tool to identify its presence in either Windows or Linux ?

There is no Wireshark-specific network protocol that it and only it
uses.

If you do a Web search for

       detecting sniffers

you can find some techniques that, although not *guaranteed* to find
programs that capture network packets, such as Wireshark (and tcpdump
and
snoop and Microsoft Network Monitor and NetScout Sniffer and
WildPackets
{Ether,Token,Airo,Omni}Peek and...), can sometimes detect those
programs on
a network.  For example:

       http://www.securiteam.com/unixfocus/2EUQ8QAQME.html

says

       How to detect other sniffers on the network

       Detecting other sniffers on other machines is very difficult
(and
sometimes impossible). But detecting whether one of the Linux machines
is
doing the sniffing is possible.
       This can be done by exploiting a weakness in the TCP/IP stack
implementation of Linux.
       When Linux is in promiscuous mode, it will answer to TCP/IP
packets sent to its IP address even if the MAC address on that packet
is
wrong (the standard behavior is that packets containing wrong MAC
address
will not be answered because the network interface will drop them).

Interesting to know that Linux TCP/IP stack implementation answers to
TCP/IP packets even if the MAC address on that packet is
wrong(Promiscuous mode). But, Is this made intentionally in Linux to
be different from standard behavior in helping the determination of
presence of sniffer in network ? Any thoughts ?

       Therefore, sending TCP/IP packets to all the IP addresses on
the
subnet, where the MAC address contains wrong information, will tell
you
which machines are Linux machines in promiscuous mode (the answer from
those
machines will be a RST packet)
While this is far from being a perfect method, it can help discover
suspicious activity on a network.


Thx in advans,
Karthik Balaguru


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Thx in advans,
Karthik Balaguru
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