On Mon, 2015-01-19 at 14:23 -0500, Miloslav Trmač wrote:
> On Fri, 2015-01-16 at 15:39 +0100, Lubomir Rintel wrote:
> >
> > There's a chance of a successful exploitation that would result
> > in obtaining my privileges. Sure, gaining access to my account
> > is bad enough, but if I run "su" or "sudo", they have
root!
>
> Along these lines, someone pointed out a rather nasty attack
> vector via sudo the other day:
>
>
http://blog.grdryn.me/blog/fedora/prank-alias-sudo-in-bash.html
>
> so...you'd better remember to call it with \ every time...:)
This is a „movie plot threat“, proposing a specific attack and a
specific mitigation, but doing nothing about the immediately
available alternative attacks. For example, I could edit ~/.profile
to replace the running bash with a modified copy that ignores (or
even specifically hijacks) the \ in \sudo.
At a first glance it seems to me there in principle can’t be a way
to protect against a modified shell environment from within that
environment because that environment can lie to you about any system
output, or to the system about any your input. (So even having a
trusted “antivirus service” running outside of the shell and
protected against it wouldn’t be useful because from the shell you
could never be sure that you are talking to that trusted service.¹)
Mirek
Sure, I just meant it as a handy and clear demonstration of the
principle that if you can compromise the environment of a user with
sudo or other admin privileges, you're about 97% of the way to root in
any case.
--
Adam Williamson
Fedora QA Community Monkey
IRC: adamw | Twitter: AdamW_Fedora | XMPP: adamw AT happyassassin . net
http://www.happyassassin.net