Snort mailing list archives

Re: Snort 3.0 is not detecting shell code attacks


From: Chankit Dureja <chankit.dureja () dcmail ca>
Date: Wed, 19 Jun 2019 15:13:00 +0000

Hello all,


I am working on a project where we are implementing SNORT as a detection system.


Does anyone know what all information would we need from our networks team to be able to implement it? Like 
router/switches info?


Thanks,

Chank


________________________________
From: Chankit Dureja
Sent: 19 June 2019 11:10:11
To: João Pedro; Russ Combs (rucombs); Dorian ROSSE; snort-users-bounces () lists snort org
Subject: Re: [Snort-users] Snort 3.0 is not detecting shell code attacks


Hello all,


I am working on a project where we are implementing SNORT as a detection system.


Does anyone know what all information would we need from our networks team to be able to implement it? Like 
router/switches info?


Thanks,

Chank


________________________________
From: Snort-users <snort-users-bounces () lists snort org> on behalf of Dorian ROSSE via Snort-users <snort-users () 
lists snort org>
Sent: 17 June 2019 08:48
To: João Pedro; Russ Combs (rucombs); snort-users () lists snort org
Subject: Re: [Snort-users] Snort 3.0 is not detecting shell code attacks


It web pages explain how to rules json attacks :

https://idstools.readthedocs.io/en/latest/tools/u2json.html

u2json - A unified2 to JSON converter — idstools 0.6.3 documentation - 
idstools.readthedocs.io<https://idstools.readthedocs.io/en/latest/tools/u2json.html>
idstools.readthedocs.io
The above command will operate like barnyard, reading all unified2.log files in /var/log/snort, waiting for new 
unified2 records when the end of the last file is reached.


Regards.


Dorian ROSSE.



Provenance : Courrier<https://go.microsoft.com/fwlink/?LinkId=550986> pour Windows 10



________________________________
De : João Pedro <oladj () live com pt>
Envoyé : Monday, June 17, 2019 2:23:57 PM
À : Russ Combs (rucombs); Dorian ROSSE; snort-users () lists snort org
Objet : Re: [Snort-users] Snort 3.0 is not detecting shell code attacks


OMG! It worked!!!! I added '--lua "search_engine.detect_raw_tcp = true"' to my command and worked!

Thank you so much :)

Às 12:56 de 17/06/19, Russ Combs (rucombs) escreveu:
You need to add –k none --lua "search_engine.detect_raw_tcp = true" to your command line.  Doing so gets some hits on 
1394 and 648.

Raw tcp detection is required by those rules and the checksum issue is indicated by the shutdown stats without –k none:

codec
                    total: 194402       (100.000%)
                 discards: 85883       ( 44.178%)
ipv4
             bad_checksum: 85831

An update will be out soon that removes the requirement for the raw tcp setting.

From: João Pedro <oladj () live com pt<mailto:oladj () live com pt>>
Date: Monday, June 17, 2019 at 7:29 AM
To: Dorian ROSSE <dorianbrice () hotmail fr<mailto:dorianbrice () hotmail fr>>, "snort-users () lists snort 
org<mailto:snort-users () lists snort org>" <snort-users () lists snort org<mailto:snort-users () lists snort org>>, 
Sourcefire Helpdesk <rucombs () cisco com<mailto:rucombs () cisco com>>
Subject: Re: [Snort-users] Snort 3.0 is not detecting shell code attacks


Thanks for your help. I think the community rules are enough for what I want to test. For example, the rule below seems 
enough to trigger an alert, but does not make sense to me why is not triggered...


  *   alert ip $EXTERNAL_NET any -> $HOME_NET any ( msg:"INDICATOR-SHELLCODE x86 inc ecx NOOP"; 
content:"AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA"; metadata:ruleset community; classtype:shellcode-detect; sid:1394; rev:17;

There are other rules, non-related to shell code, that are triggered, so Snort seems working. I already tested the rule 
I mentioned separately, but didn't work either.

Às 12:14 de 17/06/19, Dorian ROSSE escreveu:

Maybe community rules doesn’t enough against It attacks ?



Provenance : Courrier<https://go.microsoft.com/fwlink/?LinkId=550986> pour Windows 10



________________________________
De : Snort-users <snort-users-bounces () lists snort org><mailto:snort-users-bounces () lists snort org> de la part de 
João Pedro via Snort-users <snort-users () lists snort org><mailto:snort-users () lists snort org>
Envoyé : Monday, June 17, 2019 12:51:01 PM
À : snort-users () lists snort org<mailto:snort-users () lists snort org>; Russ Combs (rucombs)
Objet : Re: [Snort-users] Snort 3.0 is not detecting shell code attacks


Is also possible to check my config files and .pcap file in: https://we.tl/t-CL0SotgzlU

Às 11:30 de 17/06/19, João Pedro via Snort-users escreveu:

I send those files enclosed in this email. It's possible to check now my problem easily.

I run this command every time I want to test Snort:

  *   snort -r myfile.pcapng -c /usr/local/etc/snort/snort.lua -R /usr/local/etc/snort/rules/snort3-community.rules -A 
alert_json > alerts.json

I'm expecting the rule "1394" and "648" to be triggered, but is not working... In .pcap file is possible to see buffer 
overflow attacks tested by me (e.g. check the filter "tcp.dstport==50096 or tcp.dstport==50098").

What is the problem?

Às 02:26 de 17/06/19, Russ Combs (rucombs) escreveu:

Please send pcap, rules, config so we can help you out.

On 6/16/19, 7:39 PM, "Snort-users on behalf of João Pedro via Snort-users"
<snort-users-bounces () lists snort org on behalf of
snort-users () lists snort org><mailto:snort-users-bounces@lists.snort.orgonbehalfofsnort-users () lists snort org> 
wrote:



I'm testing snort 3.0 with Community rules.
Besides triggering alerts from port scans, it is not detecting Buffer
Overflow attacks (.i.e. made with Metasploit).
Is there a problem with the current rules in Snort 3.0? Should I
activate/config something else?

Ps: I'm testing Snort from .pcap files

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