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A trusted system does NOT involve which of the following?

  1. Enforcement of a security policy.
  2. Sufficiency and effectiveness of mechanisms to be able to enforce a security policy.
  3. Assurance that the security policy can be enforced in an efficient and reliable manner.
  4. Independently-verifiable evidence that the security policy-enforcing mechanisms are sufficient and effective.

Answer(s): C

Explanation:

A trusted system is one that meets its intended security requirements. It involves sufficiency and effectiveness, not necessarily efficiency, in enforcing a security policy. Put succinctly, trusted systems have (1) policy, (2) mechanism, and (3) assurance.


Reference:

HARE, Chris, Security Architecture and Models, Area 6 CISSP Open Study Guide, January 2002.



What can be described as an imaginary line that separates the trusted components of the TCB from those elements that are NOT trusted?

  1. The security kernel
  2. The reference monitor
  3. The security perimeter
  4. The reference perimeter

Answer(s): C

Explanation:

The security perimeter is the imaginary line that separates the trusted components of the kernel and the Trusted Computing Base (TCB) from those elements that are not trusted. The reference monitor is an abstract machine that mediates all accesses to objects by subjects. The security kernel can be software, firmware or hardware components in a trusted system and is the actual instantiation of the reference monitor. The reference perimeter is not defined and is a distracter.


Reference:

HARE, Chris, Security Architecture and Models, Area 6 CISSP Open Study Guide, January 2002.



A Security Kernel is defined as a strict implementation of a reference monitor mechanism responsible for enforcing a security policy. To be secure, the kernel must meet three basic conditions, what are they?

  1. Confidentiality, Integrity, and Availability
  2. Policy, mechanism, and assurance
  3. Isolation, layering, and abstraction
  4. Completeness, Isolation, and Verifiability

Answer(s): D

Explanation:

A security kernel is responsible for enforcing a security policy. It is a strict
implementation of a reference monitor mechanism. The architecture of a kernel operating system is typically layered, and the kernel should be at the lowest and most primitive level.
It is a small portion of the operating system through which all references to information and all changes to authorizations must pass. In theory, the kernel implements access control and information flow control between implemented objects according to the security policy.
To be secure, the kernel must meet three basic conditions:
completeness (all accesses to information must go through the kernel), isolation (the kernel itself must be protected from any type of unauthorized access), and verifiability (the kernel must be proven to meet design specifications).
The reference monitor, as noted previously, is an abstraction, but there may be a reference validator, which usually runs inside the security kernel and is responsible for performing security access checks on objects, manipulating privileges, and generating any resulting security audit messages.
A term associated with security kernels and the reference monitor is the trusted computing base (TCB). The TCB is the portion of a computer system that contains all elements of the system responsible for supporting the security policy and the isolation of objects. The security capabilities of products for use in the TCB can be verified through various evaluation criteria, such as the earlier Trusted Computer System Evaluation Criteria (TCSEC) and the current Common Criteria standard.
Many of these security terms--reference monitor, security kernel, TCB--are defined loosely by vendors for purposes of marketing literature. Thus, it is necessary for security professionals to read the small print and between the lines to fully understand what the vendor is offering in regard to security features.
TIP FOR THE EXAM:
The terms Security Kernel and Reference monitor are synonymous but at different levels.
As it was explained by Diego:
While the Reference monitor is the concept, the Security kernel is the implementation of such concept (via hardware, software and firmware means).
The two terms are the same thing, but on different levels: one is conceptual, one is "technical"
The following are incorrect answers:
Confidentiality, Integrity, and Availability
Policy, mechanism, and assurance
Isolation, layering, and abstraction


Reference:

Hernandez CISSP, Steven (2012-12-21). Official (ISC)2 Guide to the CISSP CBK, Third Edition ((ISC)2 Press) (Kindle Locations 13858-13875). Auerbach Publications. Kindle Edition.



What can best be defined as the detailed examination and testing of the security features of an IT system or product to ensure that they work correctly and effectively and do not show any logical vulnerabilities, such as evaluation criteria?

  1. Acceptance testing
  2. Evaluation
  3. Certification
  4. Accreditation

Answer(s): B

Explanation:

Evaluation as a general term is described as the process of independently assessing a system against a standard of comparison, such as evaluation criteriA. Evaluation criterias are defined as a benchmark, standard, or yardstick against which accomplishment, conformance, performance, and suitability of an individual, hardware, software, product, or plan, as well as of risk-reward ratio is measured.
What is computer security evaluation?
Computer security evaluation is the detailed examination and testing of the security features of an IT system or product to ensure that they work correctly and effectively and do not show any logical vulnerabilities. The Security Target determines the scope of the evaluation. It includes a claimed level of Assurance that determines how rigorous the evaluation is.
Criteria
Criteria are the "standards" against which security evaluation is carried out. They define several degrees of rigour for the testing and the levels of assurance that each confers. They also define the formal requirements needed for a product (or system) to meet each Assurance level.
TCSEC
The US Department of Defense published the first criteria in 1983 as the Trusted Computer Security Evaluation Criteria (TCSEC), more popularly known as the "Orange Book". The current
issue is dated 1985. The US Federal Criteria were drafted in the early 1990s as a possible replacement but were never formally adopted.
ITSEC
During the 1980s, the United Kingdom, Germany, France and the Netherlands produced versions of their own national criteriA. These were harmonised and published as the Information Technology Security Evaluation Criteria (ITSEC). The current issue, Version 1.2, was published by the European Commission in June 1991. In September 1993, it was followed by the IT Security Evaluation Manual (ITSEM) which specifies the methodology to be followed when carrying out ITSEC evaluations.
Common Criteria
The Common Criteria represents the outcome of international efforts to align and develop the existing European and North American criteria. The Common Criteria project harmonises ITSEC, CTCPEC (Canadian Criteria) and US Federal Criteria (FC) into the Common Criteria for Information Technology Security Evaluation (CC) for use in evaluating products and systems and for stating security requirements in a standardised way. Increasingly it is replacing national and regional criteria with a worldwide set accepted by the International Standards Organisation (ISO15408).
The following answer were not applicable:
Certification is the process of performing a comprehensive analysis of the security features and safeguards of a system to establish the extent to which the security requirements are satisfied. Shon Harris states in her book that Certification is the comprehensive technical evaluation of the security components and their compliance for the purpose of accreditation.
Wikipedia describes it as: Certification is a comprehensive evaluation of the technical and non- technical security controls (safeguards) of an information system to support the accreditation process that establishes the extent to which a particular design and implementation meets a set of specified security requirements
Accreditation is the official management decision to operate a system. Accreditation is the formal declaration by a senior agency official (Designated Accrediting Authority (DAA) or Principal Accrediting Authority (PAA)) that an information system is approved to operate at an acceptable level of risk, based on the implementation of an approved set of technical, managerial, and procedural security controls (safeguards).
Acceptance testing refers to user testing of a system before accepting delivery.


Reference:

HARE, Chris, Security Architecture and Models, Area 6 CISSP Open Study Guide, January 2002.
and
https://en.wikipedia.org/wiki/Certification_and_Accreditation and
http://www.businessdictionary.com/definition/evaluation-criteria.html and
http://www.cesg.gov.uk/products_services/iacs/cc_and_itsec/secevalcriteria.shtml






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