On Mon, 2002-05-13 at 09:54, Ilia A. wrote:
> > Now you are really starting to stretch it. I am sure the ratio of
> > customers that have db backends are much smaller than general webhosting
> > customers
> 
> PHP is very commonly used with a database (MySQL). I'd venture to say that 70% 
> of people who actively use PHP use it with MySQL or another database system.

You are probably correct about that.
> >
> > In all of these scenarios, the webserver itself would just spawn another
> > process, and the os would page the other one because it is not in use,
> > and then eventually the webserver would log the problem.
> >
> > If you factor that in with a shared environment with multiple webservers
> > and a load balance, your risk is pretty low. Even if someone did do
> > something like that to kill all of your webservers, you would easily be
> > able to find out who did it, and fix the abuser.
> 
> You could track down the abusee easily, simply using Apache's server-status to 
> see what each process is doing. But if you are tracking down the abuser you 
> are already too late because the problem had already occured and now you are 
> doing damage control. Sure you remove this user, but what about the next one?
> 
> > how are you planning on protecting your passwd file then?
> 
> Simple, use the file permissions to prevent the webserver from accessing it. 
> Or put the webserver inside a chroot jail, so it cannot even see parts of the 
> OS.
>

All processes have to have access to /etc/passwd. Try disabling access
to it, everything will break because all uid calls will fail

I was pointing out that OS permissions can not fix the problem. 

Yes, you can perform a chroot(), however then you have to use php as a
cgi which kills performance. Though wrapping a fastcgi interpreter with
suexec might be a much better solution.When you do build a chroot area
you have to put a bogus /etc/passwd. Both open_basedir and safe_mode
protect /etc/passwd. 

(Well for safe_mode, after the show_source() vulnerability you found was
fixed. However open_basedir still would have prevented that)

> >
> > > If you have sensetive data, like credit card information and you are not
> > > using a dedicated server to store that data then do be surprised to find
> > > your data in someone elses hands. In a shared enviroment especially where
> > > programming/scripting languages are avaliable it is merely a matter of
> > > time before someone takes advantage of some security hole/oversight and
> > > grabs the hold of your data.
> >
> > So then you are agreeing : )
> 
> If your making a point about people with sensetive data needing their own 
> servers, then yes, I whole heartedly agree with you.
> 
> > Or you could try something more useful, like fixing a bug in safe mode,
> > adding a new security feature, etc. etc. However, I suppose it is too
> > difficult to come up with a constructive solution.
> 
> I believe fixing bug in safe_mode is a pointless process because new ones will 
> appear instantly. Safe mode bugs have been fixed in every release since it 
> was first introduced and we still have problem. 
> 
> > Hmm, but you just said that a shared webhosting enviroment, by nature,
> > has no real safety.
> 
> It doesn't.
> 
> >
> > Pointlesly difficult.....
> > then safe mode must be doing something....
> 
> Yeah it is, making development a little slower because you need to make 
> safe_mode work arounds.
Yes that is unfortunate that restrictions can make development more
difficult.
> Ilia 
> 
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