mailing list archives
Re: CVE Request -- vsftpd -- Do not create network namespace per connection
From: Chris Evans <scarybeasts () gmail com>
Date: Mon, 6 Jun 2011 10:14:13 -0700
On Mon, Jun 6, 2011 at 9:19 AM, Jan Lieskovsky <jlieskov () redhat com> wrote:
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
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:
Yes, I will be considering this a kernel issue.
vsftpd also uses one (or more!) process per connection. I'd have though that
a process structure plus stack etc. would be a lot more heavyweight than an
empty network namespace, but obviously not :)
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.
It's actually configurable in vsftpd.conf:
So for a short term fix, all you need is to deploy that config change.
Looking at the Changelog, network isolation was added in vsftpd-2.2.0, and
the config setting has been there from v2.2.0 as well.
Though not sure, how it would be wrt to CVE identifier(s) assignment.
Steve, could you advice here?
Thank you & Regards, Jan.
Jan iankko Lieskovsky / Red Hat Security Response Team