Re: [Security] [PATCH] kernel: make /proc/kallsyms mode 400 toreduce ease of attacking
From: Ingo Molnar
Date: Sun Nov 07 2010 - 07:51:26 EST
* Willy Tarreau <w@xxxxxx> wrote:
> On Sun, Nov 07, 2010 at 01:12:35PM +0100, Ingo Molnar wrote:
> > * Willy Tarreau <w@xxxxxx> wrote:
> > > [...]
> > >
> > > It's precisely because you're making a special case of the security bug that you
> > > want to hide bugs from user-space by cheating on version.
> > You claimed this for the second time and i'm denying it for the second time.
> > The goal of fuzzing the version inforation is _not_ to 'hide bugs from user-space by
> > cheating on version'. The goal is to introduce uncertainty to attackers, so that a
> > honeypot silent alarm can warn the admin.
> My interpretation of this mechanism is what I explained above. [...]
( Well, if it's "your interpretation" only then stop claiming that i said it. )
> [...] "Introducing uncertainty" means hiding a version so that the attacker
> doesn't precisely know which one it is and has to send a few probes to guess it.
No. The 'exploit honeypot' mechanism i outlined is really simple, and it means what
i explained already:
- attacker breaks into unprivileged user-space
- attacker runs exploit
- exploit attempt gets detected by the 'exploit honeypot' kernel code and a
(silent) warning goes to the admin (via a syslog message for example)
- attacker only sees that the attack did not succeed
This makes it _unsafe_ (for many types of attackers) to run an exploit locally.
> That's not much different than trying to fire the exploit itself. [...]
Erm, the difference is possible _detection_ via a silent alarm.
There's a huge difference between 'attempting an exploit and being caught' and 'not
even trying the exploit because based on the kernel version the attacker knows it
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