CERIAS Seminar Presentation: David Bell (Symposium Summary)
Wednesday, March 31, 2010
Summary by Robert Winkworth
"Everything I Needed to Know About Security I Learned in 1974"
Security luminary David Bell concluded this year's
Information Security Symposium with a lecture in which
he argued that while the speed and size of computers has
changed greatly across the decades, the principles
underlying the issue of security have been remarkably
constant.
With the exception of one noted MULTICS covert channel
hack, the speaker asserted no fundamentally new innovation
in computer security appeared from 1974 until 2005 (when
he retired.) Dr. Bell had done a great deal of conceptual
modeling, particularly near the beginning of his career.
This, he explained, influenced his later work in security.
In 1971, Bell, having read many classic MULTICS papers,
felt even then that "all the good stuff" had already been
done and made public. He recalled, with some amusement,
that government facilities did not always share his
awareness of these facts. Material freely available in
research libraries, when cited in military security reports,
often becomes classified as though somehow it might be
made secret anew.
Commenting on the 1972 Anderson Report, Dr. Bell noted
that a core collection of only about a dozen critical
infiltration tactics proved successful in almost every
documented penetration test. Clearly by better abstracting
these procedures into general categories of attack we could
better understand and predict them. So, Bell was called to
produce a mathematical model of computer security, but no
other details of his assignment were specified. This, he
explained, turns the technical process of testing and setting
conditions in the machine into a cultural process of
negotiating policies. "Security" is not meaningful until
defined. Likewise, threats to security must be discussed
before we can discuss their remedies. General principles of
a security model are not useful until somehow applied, and
Bell prefers to see these concrete examples before signing
off on a policy, however academically sound it may seem.
Along with Len La Padula, David Bell is probably most
widely recognized for his contribution to the Bell-La Padula
Model of secure systems. This widely influential set of
conceptual tools appears frequently in the fundamentals of
IA curricula at Purdue and probably throughout the world.
Our host was critical of those that see security as a
personnel problem, noting that this approach fails to
recognize the technical weaknesses that remain regardless of
the people involved. And coordinating the technology is
possible; Bell shows us computer systems that have never
suffered a documented breach and never required a security
patch. Unfortunately, the process of replacing an existing
infrastructure is difficult, particularly for an entrenched
bureaucracy, so the challenge facing many security
modelers is producing a plan that outlines not only the
destination but all the intermediary steps necessary to
transform an existing system to one that approaches the
level of security desired.
Many evaluators are assigned to networks the technology
of which they cannot explain. Since they cannot articulate
an effective policy for interactions between such a network
and its trusted neighbors, a common reaction to this is to
simply isolate them. As internetworking becomes
pervasive, however, this cannot remain a practical strategy.
Networks must be connected, but such connections
introduce weaknesses if they are not thoroughly
documented and regulated. How we can possibly manage
the explosive complexity of internetworks remains a
daunting question.
"We are not safe and secure today," concludes our eminent
guest. Those that claim otherwise are "either misinformed
or lying." Bell called upon us to implement more of the
sound ideas in information assurance that hitherto have
existed only as concept, and to fully acknowledge the
extent to which models such as BLP have not been fully
embodied.
Gene Spafford was on hand for today's session, and asked
for Dr. Bell's comments on the software solutions of
Rogers and Green Hills (two of the best-rated security
platforms.) Bell found both quite sound. He was
concerned, however, that neither had achieved the market
"traction" that he would like to see. He provided some
examples of how each could be more effectively introduced
to companies that might use them in live networks.
As of March 31, 2010, the [media](http://offthisweek.com/talks/20100331_CERIAS.html) presented in this lecture
is available.


