[ntp:security] Fwd: Questions about CVE-2019-11331

Danny Mayer mayer at ntp.org
Tue Apr 30 20:59:41 UTC 2019


Thinking about this some more, I don't see how an off-path attack can
succeed. A properly written ntp server will check the initial timestamp
to make sure it matches what it sent and will drop any incoming packet
that doesn't match that timestamp.

Am I confused about what this CVE is claiming?

Danny

On 4/29/19 10:43 PM, Danny Mayer wrote:
> is this the impetus for draft-gont-ntp-port-randomization-00.txt?
>
> I still don't believe that this is a vulnerability, and I'm not clear
> why we need to randomize the port. NTP has builtin protections already
> against attacks like this so I would need to understand why it is
> considered a vunerability. The contents that I was able to find online
> told me almost nothing.
>
> Danny
>
> On 4/29/19 4:41 PM, Harlan Stenn wrote:
>> On 4/29/2019 11:31 AM, stevos at nwtime.org wrote:
>>> Harlan and Matt,
>>>
>>> Should we reach out to Art Manion? 
>> Art is at CERT. This report came thru Mitre. Daniel Andolfi is the
>> most recent contact we have at Mitre.
>>
>> There are at least 2 issues here:
>>
>> - The CVE was filed and we were never notified
>> - The content of the CVE was apparently not vetted, and appears
>> to contain a number of ... bogus claims.
>>
>>> On another note, do we have the CVE#s listed in Bugzilla with the
>>> associated bugs that do get reported? Seems like more folks use the
>>> CVE# to call out bugs than they do the numbers we assign to them in
>>> Bugzilla.
>> With enough money to upgrade support.ntp.org and our bugzilla, we can
>> more easily link our bug IDs to CVEs. We use support.ntp.org and our
>> bugzilla because we *use* our bugzilla. We don't do our work from the
>> CVE website.
>>
>> H
>> --
>>> Steve
>>>
>>> -----Original Message-----
>>> From: security <security-bounces+stevos=nwtime.org at lists.ntp.org> On
>>> Behalf Of Harlan Stenn
>>> Sent: Monday, April 29, 2019 3:53 AM
>>> To: Matt Ploessel <matt.ploessel at gmail.com>; security at ntp.org
>>> Subject: [ntp:security] Fwd: Questions about CVE-2019-11331
>>>
>>> Matt,
>>>
>>> It looks like somebody opened up this CVE and never notified us.
>>>
>>> It also looks like this report is bogus, but I just heard about it in
>>> the last few minutes and I'd like to check it out before I say more.
>>>
>>> I've already heard from one big customer asking about it, as they
>>> gave it a CVSS3 score of 9.8, which seems insane and irresponsible.
>>>
>>> Not the sort of thing I want to see at 0345 when I'm about to fall
>>> asleep.
>>>
>>> H
>>>
>>> PS - I'm not sending this encrypted because our PGP key has expired
>>> and Brad hasn't had time to refresh that yet. I've asked him if he
>>> can get that done sometime "today".
>>>
>>> -------- Forwarded Message --------
>>> Return-Path: <stenn at nwtime.org>
>>> X-Original-To: stenn at nwtime.org
>>> Delivered-To: stenn at nwtime.org
>>> Received: from [10.208.75.157] (75-139-194-196.dhcp.knwc.wa.charter.com
>>> [75.139.194.196]) (using TLSv1 with cipher AES256-SHA (256/256 bits))
>>> (No client certificate requested) by chessie.everett.org (Postfix)
>>> with ESMTPSA id 44t1VS3XtgzL7N; Mon, 29 Apr 2019 10:44:00 +0000 (UTC)
>>> Subject: Re: Questions about CVE-2019-11331
>>> From: Harlan Stenn <stenn at nwtime.org>
>>> To: Marius Rohde <marius.rohde at meinberg.de>
>>> Cc: Steve Sullivan <stevos at nwtime.org>
>>> References: <1747911970-17953 at srv-kerioconnect.py.meinberg.de>
>>> <2d2b3cfb-a8eb-f7aa-f832-ebcc33de8b5f at nwtime.org>
>>> Openpgp: preference=signencrypt
>>> Autocrypt: addr=stenn at nwtime.org; prefer-encrypt=mutual; keydata=
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>>> Message-ID: <f7f8449c-5440-334f-0e0c-e97628354e44 at nwtime.org>
>>> Date: Mon, 29 Apr 2019 03:43:58 -0700
>>> User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:60.0) Gecko/20100101
>>> Thunderbird/60.6.1
>>> MIME-Version: 1.0
>>> In-Reply-To: <2d2b3cfb-a8eb-f7aa-f832-ebcc33de8b5f at nwtime.org>
>>> Content-Type: text/plain; charset=utf-8
>>> Content-Language: en-US
>>> Content-Transfer-Encoding: 8bit
>>>
>>> Hi Marius,
>>>
>>> Nobody told us about this one.
>>>
>>> I'm not certain yet, but this seems completely bogus to me.
>>>
>>> I'll loop in some wizards and see what I can find.
>>>
>>> H
>>>
>>> On 4/29/2019 3:35 AM, Harlan Stenn wrote:
>>>> Hi Marius,
>>>>
>>>> On 4/29/2019 1:37 AM, Marius Rohde wrote:
>>>>> Hi Harlan,
>>>>>
>>>>> we have seen that the problem with the standard port usage is rated
>>>>> critical in the CVE database.
>>>>> Do you have more background information? Exists a known exploit,
>>>>> that is able to do a ntp path-off attack?
>>>> Which bug corresponds to this CVE report? I'm not seeing it in any
>>>> of our content.
>>>>
>>>> H
>>>> --
>>>>> Thank you in advance.
>>>>>
>>>>> Mit freundlichem Gruß / With kind regards *Marius Rohde*
>>>>>
>>>>> *MEINBERG Funkuhren GmbH & Co. KG*
>>>>> Lange Wand 9
>>>>> D-31812 Bad Pyrmont, Germany
>>>>> Phone: +49 (0)5281 9309-485
>>>>> Fax: +49 (0)5281 9309-230
>>>>> Amtsgericht Hannover 17HRA 100322
>>>>> Geschäftsführer: Günter Meinberg, Werner Meinberg, Andre Hartmann,
>>>>> Heiko Gerstung
>>>>> Email: marius.rohde at meinberg.de <http://marius.rohde@meinberg.de>
>>>>> Internet: www.meinberg.de <https://www.meinberg.de> /
>>>>> www.meinbergglobal.com <https://www.meinbergglobal.com> /
>>>>> www.meinberg.academy <https://www.meinberg.academy>
>>>>>
>>>>> ---------------------------------------------------------------------
>>>>> --- *MEINBERG - Solutions for Time and Frequency Synchronization*
>>>>>
>>> --
>>> Harlan Stenn, Network Time Foundation
>>> http://nwtime.org - be a Member!
>>> _______________________________________________
>>> security mailing list
>>> security at lists.ntp.org
>>> http://lists.ntp.org/listinfo/security
>>>
>
>
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