Snort mailing list archives
Re: Snort 2.9.6.2 inline mode problem
From: James Lay <jlay () slave-tothe-box net>
Date: Wed, 27 Aug 2014 07:10:06 -0600
On Mon, 2014-08-25 at 17:18 +0000, Y M wrote:
Please post your snort.conf, sanitizing any private info. Also the command you use to run Snort. YM ______________________________________________________________________ Date: Sun, 24 Aug 2014 19:58:22 +0200 Subject: Re: [Snort-users] Snort 2.9.6.2 inline mode problem From: demonsdebason () gmail com To: snort () outlook com CC: snort-users () lists sourceforge net I have already tried with this rule: drop icmp 192.168.1.2 any -> 8.8.8.8 any (msg: "NEW TEST"; sid:10666;) Also modified 384 ICMP rule: drop icmp $EXTERNAL_NET any -> $HOME_NET any (msg:"PROTOCOL-ICMP PING"; icode:0; itype:8; metadata:ruleset community; classtype:misc-activity; sid:384; rev:8;) Set HOME_NET to any, restarted Snort and got the same crap: PING 8.8.8.8 (8.8.8.8) 56(84) bytes of data. From 8.8.8.8 icmp_seq=1 Destination Port Unreachable 64 bytes from 8.8.8.8: icmp_seq=1 ttl=46 time=40.6 msFrom 8.8.8.8 icmp_seq=2 Destination Port UnreachableFrom 8.8.8.8 icmp_seq=3 Destination Port Unreachable 64 bytes from 8.8.8.8: icmp_seq=3 ttl=46 time=40.7 ms I've set additional rule: drop icmp any any -> any any (msg: "NEW TEST"; sid:10666;) ...and am getting: PING 8.8.8.8 (8.8.8.8) 56(84) bytes of data. From 8.8.8.8 icmp_seq=1 Destination Port Unreachable 64 bytes from 8.8.8.8: icmp_seq=1 ttl=46 time=40.2 msFrom 8.8.8.8 icmp_seq=2 Destination Port UnreachableFrom 8.8.8.8 icmp_seq=3 Destination Port Unreachable From 8.8.8.8 icmp_seq=4 Destination Port Unreachable From 8.8.8.8 icmp_seq=5 Destination Port Unreachable 64 bytes from 8.8.8.8: icmp_seq=5 ttl=46 time=40.6 ms From 8.8.8.8 icmp_seq=6 Destination Port Unreachable Tried with and without normalization, works the same. Snort is blocking, but seems not to be able to drop all the traffic: 08/24-19:56:03.511103 [Drop] [**] [1:10666:0] NEW TEST [**] [Priority: 0] {ICMP} 192.168.1.2 -> 8.8.8.8 08/24-19:56:03.511145 [Drop] [**] [1:10666:0] NEW TEST [**] [Priority: 0] {ICMP} x.x.x.x -> 8.8.8.8 08/24-19:56:03.551092 [Drop] [**] [1:10666:0] NEW TEST [**] [Priority: 0] {ICMP} 8.8.8.8 -> 192.168.1.2 08/24-19:56:03.551058 [Drop] [**] [1:10666:0] NEW TEST [**] [Priority: 0] {ICMP} 8.8.8.8 -> x.x.x.x On Sun, Aug 24, 2014 at 6:29 PM, Y M <snort () outlook com> wrote: Ok, assuming you are setup this way: Internet <---> eth2 | IPS | eth1 <---> local, where eth1 and eth2 are the listening (promiscuous) interfaces and through which traffic is passing. When you force Snort into inline mode using afpacket, Snort (logically) bridges the interfaces together to let the 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). Also, do you have normalization enabled? YM ______________________________________________________________ Date: Sun, 24 Aug 2014 17:50:27 +0200 Subject: Re: [Snort-users] Snort 2.9.6.2 inline mode problem From: demonsdebason () gmail com To: snort () outlook com CC: snort-users () lists sourceforge net Here is the setup: INTERNET <--> | IPS/router | <--> | local machines | IPS box has 4 interfaces, where 2 have an address, others don't. It seemed illogical to set Snort to listen on interfaces where no traffic is passing through. When I set Snort it to use unaddressed interfaces, nothing happens meaning no alerts are recorded and ICMP echo test isn't working. Tried setting up bride interfaces and assigning the two unaddressed interface to Snort, same results. The only results I get is having Snort listening the interfaces traffic traverse though. On Sun, Aug 24, 2014 at 4:24 PM, Y M <snort () outlook com> wrote: How are you testing/connecting the client (icmp echo request sender), the sensor, and the receiver of the icmp? The NICs that Snort is using to receive --> pass/drop --> forward traffic should be inline with no IP addresses. From your description, it seems that you are using the same interface to ping the box as well as do the IPS work. P.S.: Please respond to the list and not only to myself. Its a mutual benefit. YM ______________________________________________________ Date: Sun, 24 Aug 2014 14:00:20 +0200 Subject: Re: [Snort-users] Snort 2.9.6.2 inline mode problem From: demonsdebason () gmail com To: snort () outlook com 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 () outlook com> wrote: inline. ______________________________________________ Date: Sun, 24 Aug 2014 05:02:13 +0200 From: demonsdebason () gmail com To: snort-users () 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. 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=1 ttl=64 time=0.216 ms From 192.168.1.1 icmp_seq=1 Destination Port Unreachable 64 bytes from 192.168.1.1 : icmp_seq=2 ttl=64 time=0.269 ms >From 192.168.1.1 icmp_seq=2 Destination Port Unreachable 64 bytes from 192.168.1.1 : icmp_seq=3 ttl=64 time=0.221 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=8 ttl=64 time=0.226 ms 64 bytes from 192.168.1.1 : icmp_seq=9 ttl=64 time=0.201 ms 64 bytes from 192.168.1.1 : icmp_seq=10 ttl=64 time=0.253 ms 64 bytes from 192.168.1.1 : icmp_seq=11 ttl=64 time=0.204 ms Here is my info: ,,_ -*> Snort! <*- o" )~ Version 2.9.6.2 GRE (Build 77) '''' By Martin Roesch & The Snort Team: http://www.snort.org/snort/snort-team Copyright (C) 2014 Cisco and/or its affiliates. All rights reserved. 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 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 --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=1024 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. -- Aut viam inveniam aut faciam :wq! ------------------------------------------------------------------------------ Slashdot TV. Video for Nerds. Stuff that matters. http://tv.slashdot.org/ _______________________________________________ Snort-users mailing list Snort-users () lists sourceforge net Go to this URL to change user options or unsubscribe: https://lists.sourceforge.net/lists/listinfo/snort-users Snort-users list archive: http://sourceforge.net/mailarchive/forum.php?forum_name=snort-users Please visit http://blog.snort.org to stay current on all the latest Snort news! -- Aut viam inveniam aut faciam :wq! -- Aut viam inveniam aut faciam :wq! -- Aut viam inveniam aut faciam :wq! ------------------------------------------------------------------------------ Slashdot TV. Video for Nerds. Stuff that matters. http://tv.slashdot.org/ _______________________________________________ Snort-users mailing list Snort-users () lists sourceforge net Go to this URL to change user options or unsubscribe: https://lists.sourceforge.net/lists/listinfo/snort-users Snort-users list archive: http://sourceforge.net/mailarchive/forum.php?forum_name=snort-users Please visit http://blog.snort.org to stay current on all the latest Snort news!
And additionally, was this using just straight afpacket where snort actually sets up the bridge from eth0 to eth1, or was this using nfq?
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Current thread:
- Snort 2.9.6.2 inline mode problem Debason Shockre (Aug 23)
- Re: Snort 2.9.6.2 inline mode problem Y M (Aug 23)
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- Re: Snort 2.9.6.2 inline mode problem Y M (Aug 24)
- Re: Snort 2.9.6.2 inline mode problem Debason Shockre (Aug 24)
- Re: Snort 2.9.6.2 inline mode problem Y M (Aug 24)
- Re: Snort 2.9.6.2 inline mode problem Debason Shockre (Aug 24)
- Re: Snort 2.9.6.2 inline mode problem Y M (Aug 25)
- Re: Snort 2.9.6.2 inline mode problem James Lay (Aug 27)
- Re: Snort 2.9.6.2 inline mode problem Debason Shockre (Aug 27)
- Re: Snort 2.9.6.2 inline mode problem James Lay (Aug 27)
- Re: Snort 2.9.6.2 inline mode problem Debason Shockre (Aug 27)
- Re: Snort 2.9.6.2 inline mode problem James Lay (Aug 27)
- Message not available
- Re: Snort 2.9.6.2 inline mode problem Y M (Aug 27)
- Re: Snort 2.9.6.2 inline mode problem Debason Shockre (Aug 28)
- Re: Snort 2.9.6.2 inline mode problem Y M (Aug 23)