Examination of Witnesses (Questions 309
- 319)
WEDNESDAY 10 JANUARY 2007
MR ALAN
COX AND
MR ADAM
LAURIE
Q309 Chairman:
Welcome Mr Cox and Mr Laurie. Thank you very much for coming today
and addressing our questions. Would you like to introduce yourselves
first please.
Mr Cox: My name is Alan Cox and I am here to
represent the open source community in general. That is a bit
different perhaps to representing a company but it is a broad
church and I am trying to summarise its views rather than being
a dictator of those views.
Mr Laurie: My name is Adam Laurie and I am a
director of a secure hosting data centre called The Bunker and
I am also an independent security researcher and a participant
in security conferences around the world.
Q310 Chairman:
Thank you. Would either of you like to make an opening statement
or should we go into the questions?
Mr Laurie: I would just like to say when I look
at Internet security I tend to look at it not just from the point
of view of securing the Internet but also how the Internet can
be used as an attack vector against other areas of life. I take
a very broad view. We had some examples of credit card details
being stolen by skimming and then used on the Internet and the
same can be vice versa, so I may drift off into other areas of
communication and personal security.
Q311 Chairman:
Right, good, thank you for that. Let me open with the first question
and that is: who should be responsible for keeping end user machines
secure?
Mr Cox: I would take a similar line to the Microsoft
people. Certainly there is at least a moral duty on people providing
software to do their best to produce software which is secure
and as best as possible that is fit for purpose. The problem we
have throughout all computer sciences is that we genuinely do
not know how to build a perfectly secure, useable operating system.
It is a research problem which one day will get solved and somebody
will get very rich out of it, but the current state of affairs
is that we cannot do that. Much like the way you have to maintain
a car, we rely, to an extent, on end users being able to apply
updates, in the same way your tyres wear out and you need new
tyres on a car. That is not a manufacturer responsibility; it
is an operator responsibility so you have to spread it across
the two.
Mr Laurie: I broadly agree with that. I think
it is the duty of manufacturers to make it easy for you to make
things secure. I am very pleased to see that Microsoft are now
shipping secure by default settings so the file latch is switched
on, which has been something that the open source world has also
worked their way up to. They did not start doing things that way
round but we found it is better to make the machine secure by
default. However, you do have to provide the tools, advice, timely
updates and advisories when there is a problem in order for the
user to make their own choice as to whether or not they want to
apply a particular patch or how secure they want to be. As has
already been said, there is always a tradeoff between usability
and security. What I think is very important is that we do not
try and make manufacturers or vendors responsible because there
are just too many factors for them to be aware of in an installed
user base. You ship in an operating system and users will then
stick third party products on top of that which may affect the
security of the system. There is no way that a vendor can be aware
of that and you will tend to end up in a situation where there
is finger-pointing going on, the operating system vendor will
say it is the third party software that is at fault and the third
party software vendor will say it is the operating system that
is at fault, and there will be grey areas where unexpected interactions
cause insecurity when both products on their own are perfectly
secure. It would not be fair to put that burden on the vendor.
In the open source world as well there is a particular issue with
liability. How can you make an open source vendor liable for a
product that he has given away for free? There is no contract,
there has been no consideration for delivering the software, so
there is no way to enforce liability on an open source product.
Q312 Chairman:
At the same time a larger community works on it so do you think
we should encourage people to use open source software?
Mr Laurie: Absolutely. I believe that we are
going to talk about the relative security of open source and closed
source but I do not think the issue of liability should actually
prevent you from using the software. With open source software
you can see for yourself whether it is secure or not and do something
about it if it is not. With the closed source software there is
more of a promise by the vendor that a piece of software does
what it is claiming it does. With open source it tends to be,
"Well, this is the product and you can see for yourself what
it does, but we make no promises. If you want to improve it then
join the project and help to improve the software."
Q313 Chairman:
So you would say ultimately that manufacturers supplying the software
should accept legal liability for losses caused as a result of
security holes?
Mr Laurie: No, I am saying they should not be
held liable.
Mr Cox: I do not think they can be. The response
of any rational software vendor if they were told they were liable
because of this business about adding software in combination
would create a combatorial explosion. So for example, you buy
a PC, you add a word processor, you add a media player, and you
add a couple of games. All these can interact in strange and wondrous
ways and as you add more software the combination increases. The
rational thing for a software vendor to do faced with liability
would be to forbid the installation of any third party software
on the system. That would be the only behaviour that would be
sensible. I do not know, however, whether there is an argument
in the longer term that as technology improves and as we get better
at writing secure software that the law does need to hold software
companies to higher standards, at least in terms of negligence
and areas where there is room for interaction. When talking about
the open source offer, although the open source offer is generally
given away by the people who develop it, there are companies around
that software and most people who are end users or business users
probably buy some kind of package of CD software and support rather
than necessarily just getting the software for free. The question
relates to how liability moves with the services and with the
other parts of the product. At the moment there is a strange behaviour
where if the CD is faulty you clearly have recourse. If the software
on the CD is faulty the situation is clear, but that is the same
throughout all sorts of services and non-physical goods in the
European Union. It is not just a software problem, it is a very
big problem. There are certain security people within the open
source communityalthough it is not by any means a universally
held viewwho hold the view that one of the reasons that
we have problems with computer security, as we have problems with
many other things, is where those things have no recourse, no
liability attached to them. There is nothing forcing standards
to be reached or forcing quality to happen, and providing some
kind of mechanism to persuade vendors to do the job right.
Q314 Chairman:
Do you have feelings about Wi-Fi and the fact that many people
install it without any real security on it, in terms of logging
into a local network if not being able to get into the computers
themselves? Do you think Wi-Fi should be compulsorily pre-installed
with security?
Mr Cox: I think Wi-Fi is a perfect example of
why you should have security by default. Wi-Fi is in the state
today as most vendors of Windows products were seven or eight
years ago in that the default is that security is not turned on
in most cases. Some of them now turn security on by default and
we should be glad of that because the default for any product
which has the ability to cause harm should be that the harm-causing
features are disabled, so you have to learn what you are doing
and understand what you are doing before you put yourself at risk.
Mr Laurie: It should definitely not be compulsory
because in some cases you want your Wi-Fi access point to be wide
open. There are many people who are part of a community of Wi-Fi
sharing so they not running hot-spots in a commercial environment
but they are running the equivalent of a Wi-Fi hot-spot at home
where they invite neighbours or anyone in the area to use their
Wi-Fi and in return they expect other Wi-Fi points to be available
on their travels wherever they want to use it.
Q315 Chairman:
You don't think Starbucks would like to give an access code to
everybody they sell a cup of coffee to?
Mr Laurie: Starbucks might want to worry about
people sitting in their cafes sending spam and so on so there
will always be commercial considerations as to why you might want
to protect your network. I think the question of liability again
here is potentially there should be some issue of liability for
companies shipping products that are known not to be secure and
selling them as secure products. There are some specific issues
with Wi-Fi where protocols like the WEP protocol was broken a
long time ago and yet they carried on shipping it and telling
the public that that was a secure protocol when it demonstrably
was not.
Q316 Lord Howie of Troon:
I think Mr Laurie has come fairly close to answering my question
already which is; is open source software more secure than closed
source software and if it is can you tell me why?
Mr Laurie: That is the $64 million question
and that debate will rage forever and you will get arguments on
both sides. From the open source perspective, we believe it is
more secure because it is subject to more scrutiny and peer review
and so on. You can look at the code yourself and see if it is
secure or not. You can cross-check against known problems, so
for example when an issue arises in one product you can look at
how that issue actually came to be and whether other products
are subject to the same problem. If it is a low-level library
that has been used in the compilation of that product that is
at fault, you could look at other open source products which use
the same libraries and see if they are also affected. That is
a process that routinely goes on. If there is a publication of
a security issue in product A anyone who knows the source code
will immediately go and check their own products to see if they
are also affected. So you get a very rapid dissemination of security
fixes in the open source world. As an example of the security
of an open source product, there is a web server many people will
not have heard of called Apache. Quite often when I am speaking
at a high-level conference I actually ask the question of the
room, "Who here has heard of Apache?" and maybe 10%
of the people in the room will know. I will then ask, "Who
has heard of Microsoft?"big laugh, of course everyone
knows Microsoft, and then it surprises them to learn that Apache
SSL, which is the secure web server version of it, has 70% of
the world market in secure servers. In its ten-year history there
have only been three security alerts and two of those were because
of external libraries that were being used, so there has only
ever in its 10 year history been one issue specific to Apache
SSL itself. On the other side of the coin, the closed source world
relies on what we call "security by obscurity", so you
are secure because the problem is not visible. That does not mean
the problems are not there; they are just harder to find. So talking
about the bad guys, if there is money to be made out of a security
issue the bad guys are going to find it. They will poke around
and they will dig around. Securing software by simply hiding the
source code is like putting paper on the wall and saying you cannot
find the windows. If you poke enough eventually you will pop through
a window. The other issue with closed source is there are often
commercial factors involved in whether or not they release security
information or they fix a problem. If they believe that they are
the only people who know that there is this particular security
problem they may choose to do some damage limitation not to admit
to the problem because it will damage their image too much. They
do a risk versus reward calculation and decide the three people
who are likely to find this problem or report this problem are
not going to come forward so they are not going to bother fixing
it unless it turns into a live issue. The open source world has
no such limitations because we do not care, we have no liability,
so as soon as an issue comes to light we will publish, and usually
that will be within hours of the problem coming to light. Again
the closed source world tends to take longer to react. They have
a lot of infrastructure that needs to catch up, notifying their
paying customers, printing manuals possibly, distribution and
so on, so there are a lot of factors that affect the distribution
of the fix that are harder for the closed source world to deal
with than the open source world.
Q317 Lord Howie of Troon:
When you mentioned covering over windows earlier on, you were
referring to, I presume, the security holes?
Mr Laurie: Yes so a brick wall with windows
in it and a sheet of paper over it.
Q318 Lord Howie of Troon:
If the windows which are the security holes are not covered over
are they not therefore by definition easier to find?
Mr Laurie: Absolutely, easier to find and easier
to fix. The open source world relies on scrutiny so obviously
you believe that your open source product is secure, you have
released it into the world and people are using it. If an unexpected
issue comes along it is much easier to see what is going on. You
have many eyes looking at the problem and very often an open source
problem will be fixed literally within minutes or hours of the
problem coming to light, and that fix will then be available to
the public because of the distribution mechanisms that open source
employs. It will not have to wait a month or until the next patch
Tuesday to get released to the public.
Q319 Lord Howie of Troon:
That makes you wonder. The security holes are found by what you
call the bad guys but are they necessarily identified by the good
guys at the same time?
Mr Laurie: There is a lot of research being
done not just by the bad guys but also by the good guys. The ones
the bad guys find obviously they will try and keep to themselves
but they also need to exploit them and as soon as they start exploiting
them they start leaving a trail that this problem exists and then
the good guys can come along and try and find how that problem
came to be. There is also a huge community commonly referred to
as "hackers" who are not hacking for bad, they are hacking
for good. We refer to the bad hackers as "crackers"
and everyone else as "hackers". They do it as an intellectual
challenge. This is another debate which will rage and rage, what
is the definition of a hacker, but there are hackers who do it
for the good of the community and trying to find security problems
before the bad guys do.
|