Looking for Advice on Debian Server Setup

[Mark Phillips]

I thought I would just quote the manual to see if it makes sense to follow
it (pages 35-36):

Any directory tree which a user has write permissions to, such as e.g.
/home, /tmp
and /var/tmp/, should be on a separate partition. This reduces the risk of a
user DoS
by filling up your “/” mount point and rendering the system unusable (Note:
this is
not strictly true, since there is always some space reserved for root which
a normal user
cannot fill), and it also prevents hardlink attacks.

A very good example of this kind of attacks using /tmp is detailed in The
mysteriously persistently exploitable program (contest) (
http://www.hackinglinuxexposed.com/articles/20031111.html) and The myste-
riously persistently exploitable program explained (
http://www.hackinglinuxexposed.com/articles/
20031214.html) (notice that the incident is Debian-related). It is basicly
an attack in which a local user stashes
away a vulnerable setuid application by making a hard link to it,
effectively avoiding any updates (or removal)
of the binary itself made by the system administrator. Dpkg was recently
fixed to prevent this (see 225692
(http://bugs.debian.org/225692)) but other setuid binaries (not controlled
by the package manager) are
at risk if partitions are not setup correctly.

Mark

On Mon, Apr 27, 2009 at 7:49 AM, Austin Godber <godber at uberhip.com> wrote:

> I have occasionally found it handy to have /tmp on a separate
> partition.  Mainly to ensure that /tmp doesn't fill up accidentally
> which can lead to all sorts of unpleasantness and complicate recovery.
>
> Same applies pretty much across the board and bi directionally.
>
> Though separating out partitions of course comes with slightly increased
> complexity.
>
> Austin
>
> James Finstrom wrote:
> > This was discussed a week or so ago (sorta). Generaly you want to keep
> > home on it's own partition. Never seen the rest but could see some
> > logic with var and opt not really tmp
> >
> > On 4/27/09, Mark Phillips <mark at phillipsmarketing.biz> wrote:
> >
> >> I am setting up a new server for Plone/Zope sites on a Linode VPS.
> Reading
> >> the "Securing Debian Manual" (
> >> http://www.debian.org/doc/manuals/securing-debian-howto/), it
> recommends
> >> separate partitions for /tmp, /home, /opt, and /var. I was talking with
> some
> >> of the Linode folks on IRC to find out how to set up separate
> partitions,
> >> and they felt that it was unnecessary to have separate partitions for a
> >> production server (regardless if it is on Linode or not).
> >>
> >> I am interested in any opinions on the subject from this list.
> >>
> >> Thanks!
> >>
> >> Mark
> >>
> >>
> >
> >
>
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