Follow @Openwall on Twitter for new release announcements and other news
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date: Wed, 13 Feb 2019 20:57:43 +1100
From: Aleksa Sarai <cyphar@...har.com>
To: EJ Campbell <ejc3@...izonmedia.com>
Cc: oss-security@...ts.openwall.com
Subject: Re: CVE-2019-5736: runc container breakout exploit
 code

On 2019-02-13, Aleksa Sarai <cyphar@...har.com> wrote:
> On 2019-02-13, EJ Campbell <ejc3@...izonmedia.com> wrote:
> > While fixing docker / runc is clearly the right fix, would using chattr -i
> > on runc be a quick mitigation for the issue? I believe that will prevent
> > the file from being overwritten by the exploit and Etienne Stalmans
> > verified that it helped:
> >  https://twitter.com/_staaldraad/status/1095354945073754112
> 
> The privileged user in the container could just un-set the immutable
> bit using "/proc/self/fd/..." and then open it for writing. A read-only
> filesystem would work much better.

Sorry, I forgot that CAP_LINUX_IMMUTABLE is dropped by default in
Docker. Yes that mitigation would also work.

-- 
Aleksa Sarai
Senior Software Engineer (Containers)
SUSE Linux GmbH
<https://www.cyphar.com/>

Download attachment "signature.asc" of type "application/pgp-signature" (834 bytes)

Powered by blists - more mailing lists

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.