Snort mailing list archives

Re: snort 2.8.4 and inline mode


From: Will Metcalf <william.metcalf () gmail com>
Date: Tue, 25 Aug 2009 08:17:31 -0500

What do your iptables rules look like?  What traffic are you sending
to the QUEUE target?

Setting modifysid * "^alert" | "drop" is a bad idea, and will lead to
drops without notifications for things like flowbits with no alert
that are not intended to identify malicious traffic, only for protocol
identification etc.  I would run you IDS in passive mode for a while
to weed out false positives before even considering implementing a
drop rule set.

Regards,

Will

On Tue, Aug 25, 2009 at 7:52 AM, justin joseph<justinjoseph007 () gmail com> wrote:
Hi

I have compiled from source snort 2.8.4 with --enable-inline support.

to get rules for inline mode I have downloaded ruleset using oinkmaster
with the below config file:

url = 
http://www.snort.org/pub-bin/oinkmaster.cgi/006d6ba065a1c0fe55e6e4a25d74518236a3da19/snortrules-snapshot-2.8.tar.gz
path = /bin:/usr/bin:/usr/local/bin
update_files = \.rules$|\.config$|\.conf$|\.txt$|\.map$
skipfile local.rules
skipfile deleted.rules
skipfile snort.conf
modifysid * "^alert" | "drop"


As I understand the modifysid converts all the alert rules to drop rules.

I am running this with the default config file in the etc/snort.conf
file by changing
only the paths to rules and library directories.

When I test this setup with  IDSwakeup-1.0, I don't see any drop of packets
happening.  I know this because i have commented code in inline.c with
debug prints
against drop and accept verdicts.  Also there are no alerts in the logs.

But if I ran the same setup with the same config (snort.conf) file
without the -Q option in IDS mode
with only difference in using rules with alert rules(downloaded with
oinkmaster without modifysid)
I see that there are lot of alerts when tested with IDSwakeup-1.0.

What I am doing wrong, why isn't the inline mode dropping packets that
are being alerted
in the IDS mode?  is there any configuration changes required in
snort.conf between
inline and IDS modes?

thank you
Justin

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