Security Basics mailing list archives

Re: SNMP attempts every 10 minutes


From: "Ivan ." <ivanhec () gmail com>
Date: Tue, 15 Jan 2008 16:18:58 +1100

you need to go to the workstation and have a poke around, using tools
like fport from foundstone

http://www.foundstone.com/us/resources/proddesc/fport.htm

you should be able to isolate what is generating the traffic from the box.

cheers
Ivan

On Jan 15, 2008 11:08 AM, k7 fantr <k7.fantr () gmail com> wrote:
- The switch logs indicate that IP x is failing to authenticate to it
(the switch).
- The IP x is a Windows 2000 workstation
- I do not know what is causing the attempt (trap or get) and I am not
sure how I could tell the difference via the logs:
"%SNMP-3-AUTHFAIL: Authentication failure for SNMP req from host
x.x.x.x (x.y.com)"
- I can not find any logs indicating anything regarding snmp on the workstation
- I can re-create the same error message if I do a snmp-walk from my workstation

Ultimately I am wondering if I am out of my mind to demand that due to
the suspicious behavior, and the inability to determine what it IS,
this workstation should be removed from the network and investigated
rather than left on the network until proved that it is something to
worry about.

and also if any knows of malicious code that behaves in this specific manner?

I hope this adds a little clarity.. thanks for the follow ups




On Jan 14, 2008 5:43 PM, Ivan . <ivanhec () gmail com> wrote:
Is it a SNMP-trap or SNMP-get request? There is a difference and your
email isn't clear.

SNMP-trap is sent by a device to a SNMP server

SNMP-get is a read request from a SNMP poller to a device

http://www.cisco.com/univercd/cc/td/doc/cisintwk/ito_doc/snmp.htm

I assume you mean a device is polling (SNMP-get) your core switch, and
it does not have the correct auth string. You should be able to
isolate the IP of the poller and they track down the box. It could be
a linux box running some "snmp-walk" requests.

cheers
Ivan


On 11 Jan 2008 20:33:27 -0000, <k7.fantr () gmail com> wrote:
There is a machine on our network that is trying and failing to authenticate with the snmp trap on our core 
switch every 10 minutes. I can not seem to isolate what is making the requests. Based on scans that I have run, 
there is no know malware (nothing detected anyway). No services running appear to stop the requests after being 
turned turned off, and after installing a host based firewall and reviewing the logs, as well as running 
wireshark and reviewing a 2 hour capture, I can not seem to pin point anything making requests to that switch at 
all. It is the only machine on the network of about 900 that is doing this.


I want the machine removed so that I can investigate further, but I am getting resistance from the IT Manager and 
support (no time.. not necessary..). Has anybody seen this before? Am I wrong to want this removed?


Thanks in advance.





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