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full-disclosure-uk: Re: [Full-disclosure] Two MSIE 6.0/7.0 NULL

Re: [Full-disclosure] Two MSIE 6.0/7.0 NULL pointer crashes

From: Christian Sciberras <uuf6429_at_nospam>
Date: Thu Jan 21 2010 - 16:22:41 GMT
To: Dan Kaminsky <dan@doxpara.com>

People are unreasonable, first they complain about lack of quick patches/fixes.
Next they complain about fixes crashing their system.


On Thu, Jan 21, 2010 at 5:12 PM, Dan Kaminsky <dan@doxpara.com> wrote:

> On Thu, Jan 21, 2010 at 1:53 AM, Michal Zalewski <lcamtuf@coredump.cx>
> wrote:
> >> Testing takes time. That's why both Microsoft and Mozilla test.
> >
> > Testing almost never legitimately takes months or years, unless the
> > process is severely broken; contrary to the popular claims,
> > personally, I have serious doubts that QA is a major bottleneck when
> > it comes to security response - certainly not as often as portrayed.
> There are a lot of factors that go into how long it takes to run QA.
> Here's a few (I'll leave out the joys of multivendor for now):
> 1) How widespread is the deployment? A little while ago, Google had
> an XSS on Google Maps. An hour later, they didn't. About a decade
> ago, AOL Instant Messenger had a remote code execution vulnerability.
> Eight hours later, they didn't. Say what you will about
> centralization, but it *really* makes it easier and safer to deploy a
> fix, because the environment is totally known, and you have only one
> environment. There are a couple dimensions at play here:
> a) How many versions do you need to patch?
> b) How many different deployment classes are there? If your
> developers are making a bunch of enterprise assumptions (there's a
> domain, there's group policy, there's an IT guy, etc) and the fix is
> going to Grandma, let me tell you, something's not going to work
> c) What's at stake? Your D-Link router has very different deployment
> characteristics than your Juniper router.
> 2) How complicated is the fix? Throwing in a one-liner to make sure
> an integer doesn't overflow is indeed relatively straightforward. But
> imagine an oldschool application drenched in strcpy, where you've lost
> context of the length of that buffer five functions ago. Or imagine
> the modern browser bug, where you're going up against an attacker who
> *by design* has a Turing complete capability to manipulate your object
> tree, complete with control over time. Or, worst of all, take a
> design flaw like Marsh Ray's TLS renegotiation bug. People are still
> fiddling around with figuring out how to fix that bug right, months
> later. Complexity introduces three issues:
> a) You have to fix the entire flaw, and related flaws. We've all seen
> companies who deploy fixes like "if this argument contains alert(1),
> abort". Yeah, that's not enough.
> b) You have to not introduce new flaws with your fix -- complexity
> doesn't stop increasing vulnerability just because you're doing a
> security fix.
> c) The system needs to work entirely the same after. That means you
> don't get to significantly degrade performance, usability,
> reliability, or especially compatibility. Particularly with design
> bugs, other systems grow to depend on their presence. No software
> lives in a vacuum, so you have to actually _find_ these other pieces
> of code, and make sure things still work.
> 3) How many people do you actually expect to deploy your patch?
> There's this entire continuum between "only the other developers on
> SVN", through "the people who call to complain", to "everybody who
> clicks 'I accept the risk of patching'", to "my entire customer base
> with zero user interaction whatsoever". A patch with problems 0.005%
> of the time is acceptable if 1000 people are deploying, but not if
> 1,000,000 people are deploying. Note that security research is very
> strongly correlated with deployment numbers, to the point that
> vulnerability count is much more correlated with popularity than code
> quality. So you have this interesting situation where the more your
> fix is pushed, the more scrutiny there will be upon it.
> Now, you can consider these all excuses. Believe me, QA people have
> no shortage of guys who look down on them and their problems. But
> certainly different bugs have different characteristics, and assuming
> that all things can be fixed in the same time window with the same
> output quality is just factually untrue. You might as well be
> claiming the next version of HTML5 will include an <antigravity> tag
> that will make your laptop float in the air and spin around.
> There is a balancing act. Years is, of course, ridiculous. In many
> situations, so too are a couple of weeks. If the goal is to achieve
> the best quality patches, then you want the issue _prioritized
> heavily_, but not _on public fire_. The latter encourages people to
> skip testing, and you know of course what happens when you skip
> testing?
> You end up with Gigabit Ethernet drivers that can't actually handle
> all frame lengths. (Epic Intel find from Fabian Yamaguchi. Wow.)
> Responsible disclosure has its risks. You really can be jerked around
> by a company, *especially* one that hasn't experienced the weirdness
> of an external security disclosure before. But engineering realities
> don't go away just because the suits finally got out of the way.
> Testing matters.
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