security question.

[Cliff Wells]

On Fri, 2008-04-11 at 21:26 +0100, Ed W wrote:

> 
> > IMHO it's much easier to setup a VPS (e.g. OpenVZ) than to fiddle with
> > most of the security frameworks (the most common question about SELinux
> > is how to disable it).  You get adequate isolation at minimal cost, and
> > your app runs in a fairly standard environment.
> >   
> 
> Well actually you get no extra protection against your app being broken 
> into to, you just limit the damage caused.

But that's pretty much the case no matter what you do.  The security
frameworks simply prevent a broken/hacked application from being used to
further compromise the system.  Using the example you gave earlier, to
prevent a hacked PHP application from opening a network connection. They
didn't prevent the PHP app from being hacked in the first place (nor
could they).

Things like AppArmour can help prevent particular exploits in binary
applications (specifically buffer overruns leading to the execution of
arbitrary code or reading of protected areas), but in general the
purpose of security frameworks such as SELinux and GRSEC is to limit the
damage post-exploit.  This is pretty much the same for a VPS.  The scope
and method of containment is all that differs.

Regards,
Cliff