Hi Crispin,
I agree with almost everything you say until here:
"I continue to dismiss the requirement that an 0day be found
maliciously exploiting machines, because that requires inferring
intent."
IMO, everybody in this thread is taking this from an
inside-to-outside approach, whereas a '0day' is the opposite.
If I'm on a CERT team for a corporation then I don't give a flying F
if somebody's concocted a cool exploit for a vulnerability that
hasn't been patched; and moreover, I don't know about it.
I only care if there's malicious code running around in the real
world doing damage that has no patch for the vulnerability. That's
when I have to take some action or be completely helpless and in my
mind that's the only time I consider a '0day' to have any relevance.
Let me repeat: if it's a theoretical exploit, or even if it's hit
100,000 machines but has not been reported and is not "being in the
wild", then it has no relevance to me BECAUSE I DON'T KNOW THAT IT
EXISTS and therefore to me it is not 0day.
Only through normal channels doing my daily CERT work (dCERT, FrSIRT,
Secunia, etc.) if I see an exploit on an unpatched vulnerability
doing real damage is when I would ever consider the term '0day'.
Very respectfully,
Ignacio
--- Crispin Cowan <crispin@novell.com> wrote:
Casper.Dik@Sun.COM wrote:
But then there is the important concept of the "private 0day", a
new
vulnerability that a malicious person has but has not used yet.
But the point is there is no such thing as a 0day
*vulnerability"; there's
a 0day exploit, an exploit in the wild before the vulnerability
id
discovered.
An excellent point. Sorry I overlooked that. Exploit development
today
is so fast that I tend to equate knowledge of a vulnerability with
"...
and can have an exploit by tomorrow afternoon."
Rather, I just treat "0day" as a synonym for "new vulnerability"
and
don't give a hoot about the alleged intentions of whoever
discovered it.
What makes it an "0" day is that whoever is announcing it is
first to
announce it in public. You could only invalidate the 0day claim
by
showing that the same vulnerability had previously been
disclosed by
someone else.
The point is that it is not supposed to be moniker for
vulnerabilities;
it's a moniker for exploits. In any other context it does not
make sense.
Specifically considering that "0-day exploit" is the only
definition which
holds meaning with respect to a particular exploit over time.
"An exploit
which existed before the vulnerability was publicly known".
Yes, you are right. So "0day" is a class of exploits. Specifically,
it
is the class of exploits that are developed before the first
available
patch for the vulnerability in question.
But that race condition of whether the patch or the exploit is
partially
ordered, because they could be developed independently. There is
the
special case where the person who first discovered the
vulnerability
also develops either a patch or an exploit, in which case it is
totally
ordered. But in the general case where one person discovers the
vulnerability, and two other people independently develop an
exploit and
a patch, you can't tell who finished first. All you can do is
detect who
published first.
So fair enough, an "0day exploit" is one that appears in public
before
the associated patch is published.
A "private 0day exploit" (the case I was concerned with) would be
where
someone develops an exploit, but does not deploy or publish it,
holding
it in reserve to attack others at the time of their choosing.
Presumably
if such a person wanted to keep it for very long, they would have
to
base it on a vulnerability that they themselves discovered, and did
not
publish.
I continue to dismiss the requirement that an 0day be found
maliciously
exploiting machines, because that requires inferring intent. IMHO,
a POC
exploit first posted to Bugtraq ahead of the patch counts as an
0day
exploit, unless it has been so thoroughly obfuscated that the
"proof"
part of "proof of concept" is itself BS.
Crispin
--
Crispin Cowan, Ph.D.
http://crispincowan.com/~crispin/
Director of Software Engineering http://novell.com
AppArmor Chat: irc.oftc.net/#apparmor
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