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Thu Nov 23 16:36:19 EST 2017


ng the box as well as do the IPS work.

P.S.: Please respond to the list and not only to myself. Its a mutual benef=
it.
YM

Date: Sun, 24 Aug 2014 14:00:20 +0200
Subject: Re: [Snort-users] Snort 2.9.6.2 inline mode problem

From: demonsdebason at ...11827...
To: snort at ...15979...

The same behavior when running with 'eth1:eth2'.

Yeah, the interfaces are in promiscuous, silly me.
Any ideas?



On Sun, Aug 24, 2014 at 7:34 AM, Y M <snort at ...15979...> wrote:





inline.
Date: Sun, 24 Aug 2014 05:02:13 +0200
From: demonsdebason at ...11827...
To: snort-users at lists.sourceforge.net


Subject: [Snort-users] Snort 2.9.6.2 inline mode problem

Hi all.
I've been working on my Snort IPS for some time now.=20
Noticed that 'drop' rules are working half-way, I have set the test rule to=
 drop ICMP coming to the sensor from local machine:




drop icmp 192.168.1.2 any -> 192.168.1.1 any (msg: "Test rule"; sid:110011;)

Alerts get logged and can view them via BASE, but when I ping from .2 to .1=
 I get this:
PING 192.168.1.1 (192.168.1.1) 56(84) bytes of data.




64 bytes from 192.168.1.1 : icmp_seq=3D1 ttl=3D64 time=3D0.216 ms
>From 192.168.1.1 icmp_seq=3D1 Destination Port Unreachable



64 bytes from 192.168.1.1 : icmp_seq=3D2 ttl=3D64 time=3D0.269 ms

>From 192.168.1.1 icmp_seq=3D2 Destination Port Unreachable
64 bytes from 192.168.1.1 : icmp_seq=3D3 ttl=3D64 time=3D0.221 ms




So some of them are getting 'blocked'.


When I shutdown Snort I's all fine:
64 bytes from 192.168.1.1 : icmp_seq=3D8 ttl=3D64 time=3D0.226 ms


64 bytes from 192.168.1.1
 : icmp_seq=3D9 ttl=3D64 time=3D0.201 ms

64 bytes from 192.168.1.1 : icmp_seq=3D10 ttl=3D64 time=3D0.253 ms
64 bytes from 192.168.1.1


 : icmp_seq=3D11 ttl=3D64 time=3D0.204 ms

Here is my info:


   ,,_     -*> Snort! <*-
  o"  )~   Version 2.9.6.2 GRE (Build 77)=20
   ''''    By Martin Roesch & The Snort Team: http://www.snort.org/snort/sn=
ort-team




           Copyright (C) 2014 Cisco and/or its affiliates. All rights reser=
ved.
           Copyright (C) 1998-2013 Sourcefire, Inc., et al.
           Using libpcap version 1.4.0
           Using PCRE version: 7.8 2008-09-05




           Using ZLIB version: 1.2.3
+++++++++++++++++++++++++++
snort=20=20=20
 41104  4.6  2.0 1675528 1342832 ?     Ssl  04:48   0:00 /usr/sbin/snort
 -D -i eth1::eth2 -u snort -g snort -c /etc/snort/snort.conf -Q=20
--daq-mode inline -k none

+++++++++++++++++++++++++++
# Looks like you have double colons "eth1::eth2", as opposed to one colon "=
eth1:eth2". Not sure if the double colons are causing the partial drops.



snort --daq-list
Available DAQ modules:
pcap(v3): readback live multi unpriv
ipfw(v3): live inline multi unpriv
dump(v2): readback live inline multi unpriv


afpacket(v5): live inline multi unpriv



++++++++++++++++++++++++++
snort.conf:
config policy_mode:inline
config daq: afpacket
config daq_dir: /usr/lib64/daq
config daq_mode: inline

config daq_var: buffer_size_mb=3D1024


I've tried dropping all the ICMPs in the iptables, results are as expected,=
 but Snort still logs the alerts.
Do you have any idea what is the issue here?


# Does Snort log the requests or replies or both? I would image if the NIC =
is promiscuous, then it would still see the requests.=20

--=20
Aut viam inveniam aut faciam
:wq!



---------------------------------------------------------------------------=
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_______________________________________________
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Snort-users at lists.sourceforge.net
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Please visit http://blog.snort.org to stay current on all the latest Snort =
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--=20
Aut viam inveniam aut faciam
:wq!

=20=09=09=20=09=20=20=20=09=09=20=20


--=20
Aut viam inveniam aut faciam
:wq!

=20=09=09=20=09=20=20=20=09=09=20=20=

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<body class=3D'hmmessage'><div dir=3D'ltr'><br>Ok, assuming you are setup t=
his way:<div><br></div><div>Internet <---> eth2 | IPS | eth1 <---&=
gt; local, where eth1 and eth2 are the listening (promiscuous) interfaces a=
nd through which traffic is passing. When you force Snort into inline mode =
using afpacket, Snort (logically) bridges the interfaces together to let th=
e traffic pass, otherwise drop it when matches occur. Looking again at the =
rule you have, both destinations are local. What happens if you change both=
 destinations (HOME_NET and EXTERNAL_NET) to any/any? Better, take rule sid=
:384 and modify it and try to ping an external source and see what happens.=
 For troubleshooting purposes only, run Snort with -A console or -A cmg so =
you can see whats going directly on the console (without -D).</div><div><br=
></div><div>Also, do you have normalization enabled?</div><div><br></div><d=
iv>YM<br><div><hr id=3D"stopSpelling">Date: Sun, 24 Aug 2014 17:50:27 +0200=
<br>Subject: Re: [Snort-users] Snort 2.9.6.2 inline mode problem<br>From: d=
emonsdebason at ...11827...<br>To: snort at ...15979...<br>CC: snort-users at ...8192...=
sourceforge.net<br><br><div dir=3D"ltr"><div><div><div><div><div>Here is th=
e setup:<br><br></div>INTERNET <--> | IPS/router | <--> | local=
 machines |<br><br></div>IPS box has 4 interfaces, where 2 have an address,=
 others don't. It seemed illogical to set Snort to listen on interfaces whe=
re no traffic is passing through.<br>
</div>When I set Snort it to use unaddressed interfaces, nothing happens me=
aning no alerts are recorded and ICMP echo test isn't working.<br></div>Tri=
ed setting up bride interfaces and assigning the two unaddressed interface =
to Snort, same results.<br>
</div>The only results I get is having Snort listening the interfaces traff=
ic traverse though.<br></div><div class=3D"ecxgmail_extra"><br><br><div cla=
ss=3D"ecxgmail_quote">On Sun, Aug 24, 2014 at 4:24 PM, Y M <span dir=3D"ltr=
"><<a href=3D"mailto:snort at ...15979..." target=3D"_blank">snort at ...16004...=
...</a>></span> wrote:<br>
<blockquote class=3D"ecxgmail_quote" style=3D"border-left:1px #ccc solid;pa=
dding-left:1ex;">


<div><div dir=3D"ltr">How are you testing/connecting the client (icmp echo =
request sender), the sensor, and the receiver of the icmp? The NICs that Sn=
ort is using to receive --> pass/drop --> forward traffic should be i=
nline with no IP addresses. From your description, it seems that you are us=
ing the same interface to ping the box as well as do the IPS work.<div>
<br></div><div>P.S.: Please respond to the list and not only to myself. Its=
 a mutual benefit.</div><div><br></div><div>YM<br><br><div><hr>Date: Sun, 2=
4 Aug 2014 14:00:20 +0200<br>Subject: Re: [Snort-users] Snort 2.9.6.2 inlin=
e mode problem<br>
From: <a href=3D"mailto:demonsdebason at ...11827..." target=3D"_blank">demons=
debason at ...11827...</a><br>To: <a href=3D"mailto:snort at ...15979..." target=
=3D"_blank">snort at ...15979...</a><div><div class=3D"h5"><br><br><div dir=3D=
"ltr"><div>The same behavior when running with 'eth1:eth2'.<br>
Yeah, the interfaces are in promiscuous, silly me.<br></div><div>Any ideas?=
<br></div></div><div><br><br><div>
On Sun, Aug 24, 2014 at 7:34 AM, Y M <span dir=3D"ltr"><<a href=3D"mailt=
o:snort at ...15979..." target=3D"_blank">snort at ...15979...</a>></span> wro=
te:<br><blockquote style=3D"border-left:1px #ccc solid;padding-left:1ex;">



<div><div dir=3D"ltr"><br>inline.<br><div><hr>Date: Sun, 24 Aug 2014 05:02:=
13 +0200<br>From: <a href=3D"mailto:demonsdebason at ...11827..." target=3D"_b=
lank">demonsdebason at ...11827...</a><br>To: <a href=3D"mailto:snort-users at ...6193...=
sts.sourceforge.net" target=3D"_blank">snort-users at lists.sourceforge.net</a=
><br>

Subject: [Snort-users] Snort 2.9.6.2 inline mode problem<div><div><br><br><=
div dir=3D"ltr"><div><div><div><div><div><div><div>Hi all.<br></div>I've be=
en working on my Snort IPS for some time now. <br></div>Noticed that 'drop'=
 rules are working half-way, I have set the test rule to drop ICMP coming t=
o the sensor from local machine:<br>



</div>drop icmp 192.168.1.2 any -> 192.168.1.1 any (msg: "Test rule"; si=
d:110011;)<br><br></div>Alerts get logged and can view them via BASE, but w=
hen I ping from .2 to .1 I get this:<br>PING 192.168.1.1 (192.168.1.1) 56(8=
4) bytes of data.<br>



64 bytes from <a href=3D"http://192.168.1.1" target=3D"_blank">192.168.1.1<=
/a><div style=3D"width:16px;min-height:16px;display:inline-block;"> </=
div>: icmp_seq=3D1 ttl=3D64 time=3D0.216 ms<br>From 192.168.1.1 icmp_seq=3D=
1 Destination Port Unreachable<br>


64 bytes from <a href=3D"http://192.168.1.1" target=3D"_blank">192.168.1.1<=
/a><div style=3D"width:16px;min-height:16px;display:inline-block;"> </=
div>: icmp_seq=3D2 ttl=3D64 time=3D0.269 ms<br>
>From 192.168.1.1 icmp_seq=3D2 Destination Port Unreachable<br>64 bytes =
from <a href=3D"http://192.168.1.1" target=3D"_blank">192.168.1.1</a><div s=
tyle=3D"width:16px;min-height:16px;display:inline-block;"> </div>: icm=
p_seq=3D3 ttl=3D64 time=3D0.221 ms<br>


<br></div>So some of them are getting 'blocked'.<br><br></div>
When I shutdown Snort I's all fine:<br>64 bytes from <a href=3D"http://192.=
168.1.1" target=3D"_blank">192.168.1.1</a><div style=3D"width:16px;min-heig=
ht:16px;display:inline-block;"> </div>: icmp_seq=3D8 ttl=3D64 time=3D0=
.226 ms<br>

64 bytes from <a href=3D"http://192.168.1.1" target=3D"_blank">192.168.1.1<=
/a><div style=3D"width:16px;min-height:16px;display:inline-block;">
 </div>: icmp_seq=3D9 ttl=3D64 time=3D0.201 ms<br>
64 bytes from <a href=3D"http://192.168.1.1" target=3D"_blank">192.168.1.1<=
/a><div style=3D"width:16px;min-height:16px;display:inline-block;"> </=
div>: icmp_seq=3D10 ttl=3D64 time=3D0.253 ms<br>64 bytes from <a href=3D"ht=
tp://192.168.1.1" target=3D"_blank">192.168.1.1</a><div style=3D"width:16px=
;min-height:16px;display:inline-block;">


 </div>: icmp_seq=3D11 ttl=3D64 time=3D0.204 ms<br><br></div>Here is m=
y info:<br>
<br>   ,,_     -*> Snort! <*-<br> =
 o"  )~   Version 2.9.6.2 GRE (Build 77) <br>   ''=
''    By Martin Roesch & The Snort Team: <a href=3D"http=
://www.snort.org/snort/snort-team" target=3D"_blank">http://www.snort.org/s=
nort/snort-team</a><br>



           Copyright (C) =
2014 Cisco and/or its affiliates. All rights reserved.<br>  &nbsp=
;        Copyright (C) 1998-2013 Sourcef=
ire, Inc., et al.<br>         =
  Using libpcap version 1.4.0<br>      &=
nbsp;    Using PCRE version: 7.8 2008-09-05<br>



           Using ZLIB ver=
sion: 1.2.3<br>+++++++++++++++++++++++++++<br>snort   
 41104  4.6  2.0 1675528 1342832 ?     Ssl&nb=
sp; 04:48   0:00 /usr/sbin/snort
 -D -i eth1::eth2 -u snort -g snort -c /etc/snort/snort.conf -Q=20
--daq-mode inline -k none<br>
+++++++++++++++++++++++++++</div><div dir=3D"ltr"><br></div></div></div><di=
v dir=3D"ltr"># Looks like you have double colons "eth1::eth2", as opposed =
to one colon "eth1:eth2". Not sure if the double colons are causing the par=
tial drops.</div>

<div><div dir=3D"ltr"><br></div><div dir=3D"ltr"><br><div>snort --daq-list<=
br>Available DAQ modules:<br>pcap(v3): readback live multi unpriv<br>ipfw(v=
3): live inline multi unpriv<br>dump(v2): readback live inline multi unpriv=
<br>

afpacket(v5): live inline multi unpriv<br>

<br>++++++++++++++++++++++++++<br></div><div>snort.conf:<br><br clear=3D"al=
l"></div><div>config policy_mode:inline<br>config daq: afpacket<br>config d=
aq_dir: /usr/lib64/daq<br>config daq_mode: inline<br>
config daq_var: buffer_size_mb=3D1024<br><br></div><div><br></div><div>I've=
 tried dropping all the ICMPs in the iptables, results are as expected, but=
 Snort still logs the alerts.<br></div>Do you have any idea what is the iss=
ue here?</div>

<div dir=3D"ltr"><br></div></div><div dir=3D"ltr"># Does Snort log the requ=
ests or replies or both? I would image if the NIC is promiscuous, then it w=
ould still see the requests. <div><br clear=3D"all">
<br>-- <br>Aut viam inveniam aut faciam<br>:wq!<br>
</div></div>
<br>-----------------------------------------------------------------------=
-------
Slashdot TV.=20=20
Video for Nerds.  Stuff that matters.
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g/</a><br>_______________________________________________
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Please visit <a href=3D"http://blog.snort.org" target=3D"_blank">http://blo=
g.snort.org</a> to stay current on all the latest Snort news!</div> 		 	   =
		  </div></div>
</blockquote></div><br><br clear=3D"all"><br>-- <br>Aut viam inveniam aut f=
aciam<br>:wq!<br>
</div></div></div></div></div> 		 	   		  </div></div>
</blockquote></div><br><br clear=3D"all"><br>-- <br>Aut viam inveniam aut f=
aciam<br>:wq!<br>
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