oss-security - Re: CVE Request -- vsftpd -- Do not create network namespace per connection

Follow @Openwall on Twitter for new release announcements and other news

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <4E327DFF.5060803@redhat.com>
Date: Fri, 29 Jul 2011 11:31:43 +0200
From: Jan Lieskovsky <jlieskov@...hat.com>
To: oss-security@...ts.openwall.com, Greg KH <greg@...ah.com>
CC: Eugene Teo <eugene@...hat.com>, Josh Bressers <bressers@...hat.com>,
        Chris Evans <scarybeasts@...il.com>, Kees Cook <kees@...ntu.com>,
        "Steven M. Christey" <coley@...us.mitre.org>
Subject: Re: CVE Request -- vsftpd -- Do not create network
 namespace per connection


Hello Greg,

   you earlier mentioned this has been already fixed in newer kernels:

> This should already be fixed in the kernel, it looks like it's just
> older kernels that has the issue, if the distro enabled that specific
> option, so there's really nothing that needs to be done here, or a CVE
> assigned that I can tell, right?
>
> thanks,
>
> greg k-h

So the solution you describe above would be just disabling the net_ns
or some other fix? If the latter holds, could you point us to the 
relevant commit?

Thank you && Regards, Jan.
--
Jan iankko Lieskovsky / Red Hat Security Response Team

On 07/29/2011 10:37 AM, Eugene Teo wrote:
> On 06/07/2011 02:28 AM, Josh Bressers wrote:
>>
>> ----- Original Message -----
>>> Hello, Josh, Steve, vendors,
>>>
>>> It was found that vsftpd, Very Secure FTP daemon, when the network
>>> namespace (CONFIG_NET_NS) support was activated in the kernel, used to
>>> create a new network namespace per connection. A remote attacker could
>>> use this flaw to cause a memory pressure and denial of the vsftpd
>>> service.
>>>
>>> References:
>>> [1] http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=629373
>>> [2] https://bugs.launchpad.net/ubuntu/+source/linux/+bug/720095
>>> [3] https://bugzilla.redhat.com/show_bug.cgi?id=711134
>>>
>>> This one being a bit tricky one -- from my understanding of the issue,
>>> vsftpd doesn't necessarily have a security flaw on its side. It's
>>> kernel issue / bug, which allows this to be used for vsftpd DoS:
>>> [4]
>>> https://bugs.launchpad.net/ubuntu/+source/linux/+bug/720095/comments/31
>>> [5]
>>> https://bugs.launchpad.net/ubuntu/+source/linux/+bug/720095/comments/32
>>>
>>> Short-term solution would be probably to address this on the vsftpd
>>> side, the long-term one then being to get this fixed in kernel.
>>>
>>> Though not sure, how it would be wrt to CVE identifier(s) assignment.
>>>
>>
>> I'm going to assign CVE-2011-2189 for the kernel. There are numerous
>> vendors shipping this bug.
>>
>> I'll leave it up to MITRE if they think vsftpd should get an ID. I don't
>> think it should myself, but they understand these corner cases better than
>> I.
>
> Kees, how are you guys fixing this? Disable net_ns and fix vsftpd? I
> wonder how other distros approach this. Any suggestions?
>
> Thanks, Eugene

Please check out the Open Source Software Security Wiki, which is counterpart to this mailing list.

Confused about mailing lists and their use? Read about mailing lists on Wikipedia and check out these guidelines on proper formatting of your messages.