Re: [Xen-devel] Security discussion: Summary of proposals and criteria (was Re: Security vulnerability process, and CVE-2012-0217)

[Joanna Rutkowska <joanna@xxxxxxxxxxxxxxxxxxxxxx>]

On 07/12/12 18:34, Stefano Stabellini wrote:
> On Mon, 9 Jul 2012, Joanna Rutkowska wrote:
>> > On 07/09/12 15:51, Tim Deegan wrote:
>>> > > At 13:31 +0200 on 09 Jul (1341840671), Joanna Rutkowska wrote:
>>>>> > >> > If you're into security industry (going to conferences, etc) you
>>>>> > >> > certainly know the right people who would be delight to buy 
>>>>> > >> > exploits
>>>>> > >> > from you, believe me ;) Probably most Xen developers don't fit 
>>>>> > >> > into this
>>>>> > >> > crowd, true, but then again, do you think it would be so hard for 
>>>>> > >> > an
>>>>> > >> > interested organization to approach one of the Xen developers on 
>>>>> > >> > the
>>>>> > >> > pre-disclousure list? How many would resist if they had a chance 
>>>>> > >> > to cash
>>>>> > >> > in some 7-figure number for this (I read in the press that hot
>>>>> > >> > bugs/exploits sell for this amount actually)?
>>> > > I think the argument is that an exploit that's going to be public (and
>>> > > patched) in the next couple of weeks would not fetch the same kind of
>>> > > price as a unknown attack that can be kept for later.
>> > 
>> > Depending on the type of an exploit. For client-side exploits, perhaps
>> > you're right. But for infrastructure attacks it's a different story --
>> > having an exploit such the Rafal's one, I could have *silently* exploit
>> > lots of AWS machines and install backdoors in their hypervisors/dom0.
>> > The fact that they will patch the bug two weeks later might be
>> > irrelevant then.
>> > 
>> > After all, how are you going to check whether your physical server has
>> > been compromised? Most people don't use any form of trusted boot, but
>> > even if they did, it's not a silver bullet as we have demonstrated a few
>> > times in a row. And if you don't have trusted boot, as most people, you
>> > have very little chances to detect a custom-made backdoor. Even if you
>> > are allowed to reboot the machine and boot "good known binaries", which
>> > often you cannot do, are you going to manually audit all the firmware,
>> > ACPI tables, etc? Not to mention about the integrity of the actual VMs,
>> > that might have also got compromised (and checking for integrity of a
>> > running OS, such as Linux or Windows, is just undoable).
>> > 
>> > Having that said, 2 weeks might be a bit short to prepare such an
>> > advanced attack. In this respect, it would be probably beneficial to
>> > keep the embargo period as short as possible (that still allows
>> > important players to patch before others). 1 week perhaps?
> I agree on the short embargo period and I am not against having a list.
> 
> However I don't think that the list should be limited to the "important
> players". How do we define an "important player"?
> If we decide that important players are the big ones, suddenly big
> players become the only ones that can be entrusted with sentive
> informations.
> 
> Any distros can join linux-distros, no matter the size.

I didn't say the list should be limited to the important players -- I
said it likely makes no harm, from the security standpoint, if we
allowed select "important" _service providers_ to patch before others
(because, again, the world doesn't see what Xen binaries are running on
their servers, and so this doesn't leak out info about the bug, at least
it shouldn't in most cases).

I think that the list should essentially contain only some core Xen
devels and all the software vendors that _are known_ to build and
distribute products on top of Xen (such as qubes-os.org ;) Perhaps the
"important" service providers could be brought in on a case-by-case basis.

joanna.

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