3.6. Universal Participation
In order to be fully effective,
most security systems require the
universal
participation (or at least the absence of active
opposition) of a site's personnel. If someone can simply opt
out of your security mechanisms, then an attacker may be able to
attack you by first attacking that exempt person's system and
then attacking your site from the inside. For example, the best
firewall in the world won't protect you if someone who sees it
as an unreasonable burden sets up a back door connection between your
site and the Internet in order to circumvent the firewall. This can
be as easy as buying a modem, obtaining free PPP or SLIP software off
the Internet, and paying a few dollars a month to a local low-end
Internet service provider; this is well within the price range and
technical abilities of many users and managers.
uch more mundane forms of rebellion will still ruin your security.
You need everybody to report strange happenings that might be
security-related; you can't see everything. You need people to
choose good passwords; to change them regularly; and not to give them
out to their friends, relatives, and pets.
How do you get everyone to participate? Participation might be
voluntary (you convince everybody that it's a good idea) or
involuntary (someone with appropriate authority and power tells them
to cooperate or else), or some combination of the two. Obviously,
voluntary participation is strongly preferable to involuntary
participation; you want folks helping you, not looking for ways to
get around you. This means that you may have to work as an evangelist
within your organization, selling folks on the benefits of security
and convincing them that the benefits outweigh the costs.
People who are not voluntary participants will go to amazing lengths
to circumvent security measures. On one voicemail system that
required passwords to be changed every month, numerous people
discovered that it recorded only six old passwords, and took to
changing their passwords seven times in a row (in seven separate
phone calls!) in order to be able to use the same password. This sort
of behavior leads to an arms race (the programmers limit the number
of times you can change your password), and soon numerous people are
sucked into a purely internal battle. You have better things to do
with your time, as do your users; it's worth spending a lot of
energy to convince people to cooperate voluntarily, because
you'll often spend just as much to force them, with worse side
effects.
| | |
3.5. Fail-Safe Stance | | 3.7. Diversity of Defense |