Security Changes For Fedora 9

[Ville Skyttä]

On Monday 14 January 2008, Eric Rannaud wrote:
> On Jan 10, 2008 10:26 PM, Ville Skyttä <ville.skytta at iki.fi> wrote:
> > On Saturday 05 January 2008, Kevin Fenzi wrote:
> > > I find root ssh login handy for a number of reasons:
> >
> > [...]
> >
> > > - It's nice to be able to do for automated tasks (like say installing a
> > > single new package on 20 machines without having to login and sudo on
> > > each).
> >
> > "ssh -t $host sudo yum install $package" works for me...
>
> What about (supposing I know the password of non-root user 'foo', and
> assuming that 'foo' can sudo yum):
>
> [hacker at tooeasy]$ rpm -q --scripts hacker_pkg.rpm
> postinstall scriptlet (using /bin/sh):
> rm -rf /
> exit 0
> [hacker at tooeasy]$ scp -p hackers_pkg.rpm foo at host:
> [hacker at tooeasy]$ ssh -t foo at host sudo yum localinstall --nogpgcheck
> ./hackers_pkg.rpm
>
> Am I wrong in assuming that yum is not necessarily a safe command to
> be used with sudo?

Not at all.

> Or more exactly, that there is no point in blocking 
> root ssh logins if you're going to let a user that can login remotely
> use sudo on yum?

Well, I was responding to the "convenience of automation" part, demonstrating 
that root SSH access is not needed for that, it can be done pretty much as 
easily with sudo; not to the security aspects per se.  But I suppose using an 
arbitrary username for those tasks instead of root and blocking direct root 
SSH (with password authentication) could make things somewhat harder for 
brute forcers.