Follow @Openwall on Twitter for new release announcements and other news
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date: Thu, 9 Oct 2014 01:05:23 +0200
From: Jann Horn <jann@...jh.net>
To: oss-security@...ts.openwall.com
Subject: Re: openssh on linux rce in sftp-only mode

On Wed, Oct 08, 2014 at 06:44:32PM -0400, Josh Bressers wrote:
> > > 
> > > I think one has to assume if a user has unrestricted sftp access, they can
> > > figure out how to do most anything. Even with the upstream hardening patch,
> > > it really only protects the sftpd process. Any other processes the user may
> > > own could be modified.
> > 
> > Not that easily - /proc/$pid/mem requires you to either be the same process
> > or be attached to it via ptrace, I think.
> > 
> 
> I can't speak for other systems (I don't understand the details), but I can
> read arbitrary process memory for processes I own in Fedora 20.

Hmm, just tried it on Debian Testing, I can reproduce that.


> Does someone know what the typical default is?

I looked through the git history of fs/proc/base.c now, looks like commit
e268337dfe26dfc7efd422a804dbb27977a3cccc ("proc: clean up and fix
/proc/<pid>/mem handling") changed the behavior to be more permissive. That commit
is between kernel 3.2 and 3.3. Meh. :(

Download attachment "signature.asc" of type "application/pgp-signature" (820 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.