Page 91 - DCAP516_COMPUTER_SECURITY

Unit 7: Designing Trusted Operating System

The Common Criteria for Information Technology Security Evaluation Notes

Also abbreviated as Common Criteria or CC is an international standard (ISO/IEC 15408) for
computer security certification. It is currently in version 3.1.
Common Criteria is a framework in which computer system users can specify their security
functional and assurance requirements, vendors can then implement and/or make claims about
the security attributes of their products, and testing laboratories can evaluate the products to
determine if they actually meet the claims. In other words, Common Criteria provides assurance
that the process of specification, implementation and evaluation of a computer security product
has been conducted in a rigorous and standard manner.
Recognition Agreement with 5 signers namely US, UK, Canada, France and Germany. But as of
May 2002, 10 more signers i.e. Australia, Finland, Greece, Israel, Italy, Netherlands, New Zealand,
Norway, Spain, Sweden; India, Japan, Russia, South Korea developing appropriate schemes.
The TCSEC defined a number of levels of assurance:

D – basically, no protection. Any system can get this level.
C1– discretionary access control
C2– controlled access protection (a finer grained discretionary access control)
B1 – labeled security protection

Each object is assigned a security level and mandatory access controls are used.
B2 – structured protection. This is level B1 with formal testing of a verified design.
B3 – security domains. The security kernel must be small and testable.
A1– verified design. A formal design exists and has been thoroughly examined.

The TCSEC was a good document for its day, but it was overtaken by the arrival of the Internet
and connectivity to the Internet. Several operating systems were rated as C1 or better, provided
that the system was running without connection to the Internet.
More recently, the U.S. Government has published the Combined Federal Criteria, followed in
1998 by the Common Criteria. This document proposed a number of levels of assurance (seven,
I think) with higher levels being more secure and the top level being characterized as
“ridiculously secure”.

Self Assessment

Fill in the blanks:
5. There are ……………….. requirements under the accountability objective.
6. …………………………………………. is a United States Government Department of Defense
(DoD) standard that sets basic requirements for assessing the effectiveness of computer
security controls.
7. The …………………….. or DoDD 5200.28-STD was canceled by DoDD 8500.1 on October
24, 2002.
8. ……………………………. represents one of the larger vulnerabilities in operating systems.
9. Assurance criteria are specified to enable …………………….

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