nanog mailing list archives

Re: One hint - how to detect invected machines _post morten_... Re: dealing with w32/bagle


From: "James M. Kretchmar" <kretch () MIT EDU>
Date: Fri, 05 Mar 2004 13:22:03 -0500


Also take a look at Neo at http://www.ktools.org/ which is scriptable
and does all the SNMP work behind the scenes for you.  A beta of the
new 2.0 version (in Python) will be out within a week.

kretch

Solution:
- get all port statistics from switch (using SNMPGET and using simple
'telnetting' script - we have 'RUN-cmd' tool allowing to run switch commands
from shell file;
- remove all ports with traffic less than some threshold;
- calculate IN/OUT packets ratio for the rest of ports;
- find ports, where IN/OUT ratio (IN - to switch) > 6;
- in this ports, find ports with average packet size < 256 bytes;

It shows all ports with infected notebooks (even if notebook was connected
for a half of day).

PS. Of course, after this few additional monitoring tools was installed, and
we added _all_ switches and _all_ ports to 'snmpstat' monitoring system (it
allows to see a traffic in real time, and analiz historical charts,
including such things as packet size).


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