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- From: Trusted Product Evaluation Program <TPEP@dockmaster.ncsc.mil>
- Newsgroups: comp.security.misc,comp.security.unix,comp.answers,news.answers
- Subject: Computer Security Evaluation FAQ, Version 2.1
- Supersedes: <computer-security/evaluations_842859583@rtfm.mit.edu>
- Followup-To: poster
- Date: 16 Oct 1996 16:38:11 GMT
- Organization: Trusted Product Evaluation Program
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- Archive-name: computer-security/evaluations
-
- The Computer Security Evaluation Frequently Answered Questions (V2.1)
-
- This FAQ is designed to answer common questions about the evaluation of
- trusted products. It is being posted to comp.security.misc
- comp.security.unix, comp.answers and news.answers. We have attempted to be as
- clear, precise, accurate, and correct as possible. Some answers are
- undoubtedly closer to this ideal than others. Comments on the FAQ may be sent
- to TPEP@dockmaster.ncsc.mil. The current official version of this FAQ may be
- found at <http://www.radium.ncsc.mil/tpep/process/faq.html>.
-
- ----------
-
- Subject: Contents
-
- Section I: The Trusted Product Evaluation Program (TPEP)
- 1. What is the National Computer Security Center (NCSC)?
- 2. What is TPEP?
- 3. How is TPEP related to the National Security Agency (NSA)?
- 4. How is TPEP related to the National Institute of Standards
- and Technology (NIST)?
- 5. How do I contact the TPEP?
- 6. What is the TTAP?
- 7. What is Dockmaster?
- 8. Why doesn't TPEP have a WWW server on Dockmaster?
- Section II: Criteria
- 1. What is the criteria used for evaluation?
- 2. What is the TCSEC?
- 3. What is the Orange Book?
- 4. What are interpretations?
- 5. What is the Interpreted TCSEC (ITCSEC)?
- 6. What is the ITSEC (as opposed to the ITCSEC)?
- 7. What is the CTCPEC?
- 8. What is the Common Criteria?
- 9. What is the TNI?
- 10. What is the TDI?
- 11. What is the Rainbow Series?
- 12. What are Process Action Team (PAT) Guidance Working Group (PGWG)
- documents?
- 13. Is there a criteria for commercial (as opposed to military) systems?
- 14. What is the Federal Criteria?
- 15. What are the CMWREQs and the CMWEC?
- Section III: Criteria Concepts
- 1. What are security features?
- 2. What is assurance?
- 3. What is a division?
- 4. What is a class?
- 5. What is a network component?
- 6. What is a Network Security Architecture Design (NSAD) document?
- 7. How do I interpret a rating?
- 8. The TCSEC is 10 years old, doesn't that mean it's outdated?
- 9. How do the TCSEC and its interpretations apply to routers and
- firewalls?
- 10. Does a trusted system require custom hardware?
- 11. What are the requirements for a D/C1/C2/B1/B2/B3/A1 system?
- Section IV: Evaluations
- 1. How do I get my product evaluated?
- 2. What is the evaluation process?
- 3. How long does an evaluation take?
- 4. How much does an evaluation cost?
- 5. How do I find out about the evaluation process?
- 6. Who actually performs the evaluations?
- 7. What information is released about an evaluated product?
- 8. What is RAMP?
- Section V: Evaluated Products
- 1. Should I buy an evaluated product?
- 2. Does NSA buy/use evaluated products?
- 3. How do I know if a product is evaluated?
- 4. What does it mean for a product to be "in evaluation"?
- 5. What does it mean for a product to be "compliant" with the TCSEC?
- 6. What and where is the Evaluated Products List (EPL)?
- 7. How do I get a copy of an evaluation report?
- 8. Is an evaluated product "hacker proof?"
- 9. What is the rating of DOS?
- 10. What is the rating of UNIX?
- 11. What should I do if evaluated Product X appears to fail a requirement?
- 12. Why should I buy a B2/B3/A1 product over a C2/B1 product?
- 13. Is there an approved program to declassify my hard drive?
-
- ----------
-
- Subject: Section I: The Trusted Product Evaluation Program (TPEP)
-
- 1. What is the National Computer Security Center (NCSC)?
-
- The Department of Defense Computer Security Center was
- established in 1981 to encourage the widespread availability of
- trusted computer systems for use by facilities processing
- classified or other sensitive information. In August 1985 the
- name of the organization was changed to the National Computer
- Security Center (NCSC). The NCSC may be reached at:
-
- National Computer Security Center
- 9800 SAVAGE ROAD
- FT MEADE MD 20755-6000
-
- or by phone at (410) 859-4376.
-
- 2. What is TPEP?
-
- The Trusted Product Evaluation Program (TPEP) is the program by
- which the NCSC evaluates computer systems against security
- criteria. The Trusted Product Evaluation Program (TPEP) is
- operated by an organization separate from the National Computer
- Security Center (NCSC). The TPEP performs computer security
- evaluations for, and on behalf of, the NCSC.
-
- 3. How is TPEP related to the National Security Agency (NSA)?
-
- Both the Trusted Product Evaluation Program (TPEP) and the
- National Computer Security Center (NCSC) are organizational
- units within the National Security Agency (NSA). The TPEP and
- NCSC are two of a number of organizational units within the NSA
- responsible for the information system security mission with
- respect to classified and sensitive data (see
- <http://www.nsa.gov:8080/>).
-
- 4. How is TPEP related to the National Institute of Standards
- and Technology (NIST)?
-
- In Public Law 100-235 congress directed the National Security
- Agency (NSA), of which the Trusted Product Evaluation Program
- (TPEP) is a part, to lead the efforts of the United States
- Government in information systems security for classified
- information. The National Institute of Standards and Technology
- (NIST) as part of the Department of Commerce is directed to
- lead the efforts for sensitive but unclassified information
- with technical support from the NSA. The NSA and NIST have
- established a Memorandum of Understanding detailing the
- responsibilities of each organization with respect to the other
- in this area. While NSA and NIST each have individual efforts,
- the agencies attempt to develop methods and standards that are
- compatible. (see <http://csrc.ncsl.nist.gov/>)
-
- 5. How do I contact the TPEP?
-
- The Trusted Product Evaluation Program can be reached by mail at
-
- V24, TRUSTED PRODUCT EVALUATION PROGRAM
- NATIONAL SECURITY AGENCY
- 9800 SAVAGE ROAD STE 6753
- FT MEAD MD 20755-6753
-
- or by phone at (410) 859-4458.
-
- 6. What is the TTAP?
-
- The Trust Technology Assessment Program (TTAP) is a joint
- National Security Agency (NSA) and National Institute of
- Standards and Technology (NIST) effort to commercialize the
- evaluation of commercial-off-the-shelf (COTS) products at the
- lower levels of trust. Under the auspice of the National
- Voluntary Laboratory Accreditation Program (NVLAP), TTAP will
- establish, accredit and oversee commercial evaluation
- laboratories focusing initially on products with features and
- assurances characterized by the Trusted Computer System
- Evaluation Criteria (TCSEC) B1 and lower levels of trust
- (see Section II, Question 2 and Section III, Question 4).
- Vendors desiring a level of trust evaluation will contract with
- an accredited laboratory and pay a fee for their product's
- evaluation. (see <http://csrc.ncsl.nist.gov/ttap/>)
-
- TTAP approval and oversight mechanisms will assure continued
- quality and fairness. Using the NVLAP model of standardized
- testing and analysis procedures, TTAP will strive to achieve
- mutual recognition of evaluations with other nations. The
- European Community evaluations are performed under the purview
- of national test standardization bodies associated with NVLAP.
-
- The TTAP is being established with a planned transition from
- TCSEC based evaluations to Common Criteria based evaluations
- (see Section II, Question 8). The implementation of the Common
- Criteria will occur upon acceptance of the Common Criteria and
- the Common Evaluation Methodology, which is in the process of
- being developed.
-
- 7. What is Dockmaster?
-
- Dockmaster, or more precisely dockmaster.ncsc.mil, is an
- unclassified computer system used by the Trusted Product
- Evaluation Program (TPEP) to exchange information between
- product evaluators, vendors, and others within the computer
- system security community. Dockmaster is based on the
- B2-evaluated Honeywell MULTICS product. This is a very old
- platform, and efforts are underway to replace Dockmaster with a
- more current product. In addition to use by the TPEP and the
- NCSC, dockmaster provides service to the information security
- community through electronic mail, bulletin boards, and forums
- for the exchange of ideas. Online access to the INFOSEC Product
- and Services Catalogue is available. Information is provided
- about training courses and scheduled INFOSEC conferences.
-
- To register for an account, write to:
-
- Attn: Dockmaster Accounts Administrator
- National Computer Security Center
- 9800 SAVAGE ROAD
- FT MEADE MD 20755-6000
-
- 8. Why doesn't TPEP have a WWW server on Dockmaster?
-
- Many desirable network access features are not available in the
- MULTICS operating system used by Dockmaster. As the system is
- upgraded, it is anticipated that it will support some of these
- features. The TPEP WWW server is available at
- <http://www.radium.ncsc.mil/tpep/>.
-
- ----------
-
- Subject: Section II: Criteria
-
- 1. What is the criteria used for evaluation?
-
- The criteria currently used by the Trusted Product Evaluation
- Program (TPEP) to grade the security offered by a product is
- the Trusted Computer System Evaluation Criteria (TCSEC), dated
- 1985 (see Section II, Question 2)
-
- 2. What is the TCSEC?
-
- The Trusted Computer System Evaluation Criteria (TCSEC) is a
- collection of criteria used to grade or rate the security
- offered by a computer system product. The TCSEC is sometimes
- referred to as "the Orange Book" because of its orange cover.
- The current version is dated 1985 (DOD 5200.28-STD, Library No.
- S225,711) The TCSEC, its interpretations and guidelines all
- have different color covers, and are sometimes known as the
- "Rainbow Series" (see Section II, Question 11.) It is available at
- <http://www.radium.ncsc.mil/tpep/library/rainbow/5200.28-STD.html>
-
- 3. What is the Orange Book?
-
- See Section II, Question 2.
-
- 4. What are interpretations?
-
- It is often the case that there are several ways to read a
- given statement in the Trusted Computer System Evaluation
- Criteria (TCSEC). Interpretations are official statements
- articulating which of a number of possible ways to read the
- requirement are the acceptable ways for purposes of evaluation
- by the TPEP. Interpretations are developed by an group of
- highly experienced product evaluators. These interpretations
- in proposed form are available for comment by all users of
- Dockmaster (see Section 1, Question 6) including vendors with
- products in evaluation. After considering the comments and
- revising the interpretation as appropriate (sometime through
- several rounds of comments and revision) the interpretation is
- accepted by the TPEP and officially announced.
-
- 5. What is the Interpreted TCSEC (ITCSEC)?
-
- The Interpreted Trusted Computer System Evaluation Criteria
- (ITCSEC) is a version of the TCSEC maintained by the Trusted
- Product Evaluation Program (TPEP) that annotates the TCSEC
- requirements with all current interpretations. It is available
- in postscript from
- <http://www.radium.ncsc.mil/tpep/library/tpep/ITCSEC.ps>.
-
- 6. What is the ITSEC (as opposed to the ITCSEC)?
-
- The Information Technology Security Evaluation Criteria (ITSEC)
- is a European-developed criteria filling a role roughly
- equivalent to the TCSEC. While the ITSEC and TCSEC have many
- similar requirements, there are some important distinctions.
- The ITSEC places increased emphasis on integrity and
- availability, and attempts to provide a uniform approach to the
- evaluation of both products and systems. The ITSEC also
- introduces a distinction between doing the right job
- (effectiveness) and doing the job right (correctness). In so
- doing, the ITSEC allows less restricted collections of
- requirements for a system at the expense of more complex and
- less comparable ratings and the need for effectiveness analysis
- of the features claimed for the evaluation. The question of
- whether the ITSEC or TCSEC is the better approach is the
- subject of sometimes intense debate. The ITSEC is available in
- postscript at
- <http://www.radium.ncsc.mil/tpep/library/non-US/ITSEC-1.2.html>.
-
- On 21 August 1995, The National Institute of Standards and
- Technology (NIST) released a draft National Computer Systems
- Laboratoty (NCSL) Bulletin. This draft bulletin adresses the
- relationship of low assurance products evaluated under the
- TCSEC, ITSEC, and CTCPEC. In the case of the ITSEC, it is
- recommended that if an appropriate C2 rated product is not
- available, that ITSEC rated FC2/E2 products be used.
-
- 7. What is the CTCPEC?
-
- The Canadian Trusted Computer Product Evaluation Criteria is
- the Canadian equivalent of the TCSEC. It is somewhat more
- flexible than the TCSEC (along the lines of the ITSEC) while
- maintaining fairly close compatibility with individual TCSEC
- requirements. The CTCPEC is available at
- <http://www.cse.dnd.ca/Services/Criteria/English/Criteria.html>.
-
- On 21 August 1995, The National Institute of Standards and
- Technology (NIST) released a draft National Computer Systems
- Laboratoty (NCSL) Bulletin. This draft bulletin adresses the
- relationship of low assurance products evaluated under the
- TCSEC, ITSEC, and CTCPEC. In the case of the CTCPEC, it is
- recommended that if an appropriate C2 rated product is not
- available, that CTCPEC products rated with a C2 functionality
- profile and T1 assurance be used.
-
- 8. What is the Common Criteria?
-
- The Common Criteria (CC) occasionally (and somewhat
- incorrectly) referred to as the Harmonized Criteria, is a
- multinational effort to write a successor to the TCSEC and
- ITSEC that combines the best aspects of both. An initial
- version (V 1.0) was released in January of 1996. The CC has
- a structure closer to the ITSEC than the TCSEC and includes
- the concept of a "profile" to collect requirements into easily
- specified and compared sets. The TPEP is actively working to
- develop profiles and an evaluation process for the CC. We
- anticipate beginning several trial CC evaluations late in
- calendar year 1996. It is available in postscript from
- <http://www.radium.ncsc.mil/tpep/library/ccitse/>
-
- 9. What is the TNI?
-
- The Trusted Network Interpretation (TNI) of the TCSEC, also
- referred to as "The Red Book," is a restating of the
- requirements of the TCSEC in a network context. Evaluations of
- the type of systems (sometimes called distributed or
- homogeneous) described by Part I are often evaluated directly
- against the TCSEC without reference to the TNI. TNI component
- evaluations are evaluations performed against Appendix A of the
- TNI. (see Section III, Question 5) It is available in at
- <http://www.radium.ncsc.mil/tpep/library/rainbow/NCSC-TG-005.html>.
-
- 10. What is the TDI?
-
- The Trusted Database Interpretation (TDI) of the TCSEC is
- similar to the Trusted Network Interpretation (TNI) in that it
- decomposes a system into independently evaluatable components.
- It differs from the TNI in that the paradigm for this
- decomposition is the evaluation of an application (e.g.,
- database) running on an already evaluated system. The Trusted
- Product Evaluation Program (TPEP) has to date only evaluated
- databases using this interpretation. In principle arbitrary
- trusted applications could be evaluated. It is available at
- <http://www.radium.ncsc.mil/tpep/library/rainbow/NCSC-TG-021.html>.
-
- 11. What is the Rainbow Series?
-
- The "Rainbow Series" is the name given to the collection of
- interpretation documents (e.g., TNI and TDI) and guidance
- documents (e.g., Guide to understanding MAC, Password
- Guidelines) published by the National Computer Security Center
- (NCSC). Each document has a different color cover, thus the
- name "Rainbow Series." The guidelines of the rainbow series,
- are designed to expand on, and clarify, the requirements in the
- Trusted Computer System Evaluation Criteria (TCSEC). They are,
- however, only guidance. The words of the requirements and
- interpretations are used as the metric for evaluation, not the
- guidelines. A single copy of every rainbow series
- document is available without charge to U.S. addresses
- by writing to:
-
- INFOSEC AWARENESS, ATTN: Y13/IAOC
- DEPARTMENT OF DEFENSE
- 9800 SAVAGE ROAD
- FT MEADE MD 20755-6000
-
- or by calling (410) 766-8729. Additional copies may be
- obtained from the Government Printing Office. The Trusted
- Computer System Evaluation Criteria (TCSEC) and most of the
- other rainbow series documents are available at
- <http://www.radium.ncsc.mil/tpep/library/rainbow/>.
-
- 12. What are Process Action Team (PAT) Guidance Working Group (PGWG)
- documents?
-
- The PGWG (often pronounced pig-wig) documents are also known
- as the Form and Content documents. These documents are
- published directly by the Trusted Product Evaluation Program
- (TPEP) and are designed to provide guidance to vendors
- submitting products for evaluation. This guidance is not
- security or requirements guidance in the Rainbow Series style.
- Rather, these documents provide rules used by the TPEP in
- accepting products into evaluation to ensure that the
- information provided to the evaluation team is in a state that
- is most conducive to a expeditious and trouble-free
- evaluation. The document discussing design documentation is
- available in postscript at
- <http://www.radium.ncsc.mil/tpep/library/process_documents/PATdesign.ps>.
- The document discussing test documentation is available in
- postscript from
- <http://www.radium.ncsc.mil/tpep/library/process_documents/PATtest.ps>.
-
- 13. Is there a criteria for commercial (as opposed to military) systems?
-
- The Trusted Product Evaluation Program (TPEP) is prohibited by
- the Computer Security Act of 1987 from attempting to directly
- address the needs of commercial systems. The TPEP does not
- subscribe, however, to the often loudly espoused belief that
- the requirements of military systems are entirely divorced from
- the requirements of commercial systems. It seems reasonable to
- believe that commercial computer system users require many of
- the same basic features of military systems: identification and
- authentication of the users requesting information or service
- from the system; ability to audit the actions of users; and
- control of access to information, both at the discretion of the
- information owner and by corporate policy. Because the TCSEC
- couched its requirements in terms of DoD classifications, many
- people have not thought about applying them to similar needs
- for mandatory controls on protected information pertaining to
- product development, marketing, and personnel decisions. It is
- one of the aims of the Common Criteria to provide criteria that
- use more general terminology.
-
- 14. What is the Federal Criteria?
-
- The Federal Criteria was an attempt to develop a criteria to
- replace the Trusted Computer System Evaluation Criteria
- (TCSEC). A draft version was released for public comment in
- December 1992. However, this effort was supplanted by the
- Common Criteria effort (see Section II, Question 8), and the
- Federal Criteria never moved beyond the draft stage (although
- many of its ideas are retained in the Common Criteria). There
- is no FINAL Federal Criteria; the draft should not be treated
- as a final criteria document. The draft of the Federal
- Criteria is available at <http://hightop.nrl.navy.mil/rainbow.html>.
-
- 15. What are the CMWREQs and the CMWEC?
-
- The criteria used by the Defense Intelligence Agency (DIA) to
- rate a product as a Compartmented Mode Workstation (CMW) is the
- Compartmented Mode Workstation Evaluation Criteria (CMWEC),
- which superseded the CMW Requirements (CMWREQs) in 1991. This
- criteria defines a minimum level of assurance equivalent to the
- B1 level of the TCSEC (see Section III, Questions 2-4). It
- also defines a minimum set of functionality and usability
- features outside the scope of the TCSEC (e.g. a graphical user
- interface via a window system is required along with the
- capability to cut and paste between windows). Neither set of
- requirements are currently used by the Trusted Product Evaluation
- Program (TPEP) although products that are designed to have these
- features may be evaluated as B1 or higher products.
-
-
- ----------
-
- Subject: Section III: Criteria Concepts
-
- 1. What are security features?
-
- A security feature is a specific implementable function in a
- system which supports some part of the system's security
- policy. Examples of security features would be access control,
- trusted path, and audit. The Trusted Computer System
- Evaluation Criteria (TCSEC) (see Section II, Question 1)
- ratings are not designed to express the rating of individual
- features, as are some other criteria. Rather, each class
- specifies a set of security features that a system must
- implement in order to be rated at that class. However, many
- evaluations are given "extra credit" in the evaluation results
- for successful implementations of features that are required
- only in a higher overall rating in the criteria.
-
- 2. What is assurance?
-
- In the context of the Trusted Computer System Evaluation
- Criteria (TCSEC), assurance coincides with correctness
- assurance. It is a measure of confidence that the security
- features and architecture of a computer system accurately
- mediate and enforce the system security policy. The TCSEC's
- assurance-related requirements constrain development methods
- (e.g., configuration management) and software engineering
- practices (e.g., modular code). Higher evaluation classes
- contain more assurance-promoting requirements and give more
- confidence in correctness.
-
- 3. What is a division?
-
- A division is a set of classes (see Question 5) from the
- Trusted Computer System Evaluation Criteria (TCSEC) (see
- Section II, Question 1). There are 4 divisions A, B, C, and D
- in decreasing order of assurance and features. Thus, a system
- evaluated at a class in division B has more security features
- and/or a higher confidence that the features work as intended
- than a system evaluated at a class in division C. Although the
- Computer Security Subsystem Interpretation (CSSI) of the TCSEC
- specifies criteria for various D ratings, these are not
- reflected in the TCSEC itself, which has no requirements for D
- division systems. An unrated system is, by default, division
- D.
-
- 4. What is a class?
-
- A class is the specific collection of requirements in the
- Trusted Computer System Evaluation Criteria (TCSEC) to which an
- evaluated system conforms. There are seven classes in the
- TCSEC A1, B3, B2, B1, C2, C1, and D, in decreasing order of
- features and assurances. Thus, a system evaluated at class B3
- has more security features and/or greater confidence that the
- security features work as intended than a system evaluated at
- class B1. The requirements for a higher class are always a
- superset of the lower class. Thus a B2 system meets every C2
- functional requirement and has a higher level of assurance.
-
- 5. What is a network component?
-
- A "network component" is the target of evaluation for a Trusted
- Network Interpretation (TNI) evaluation (see Section II,
- Question 9) done against appendix A of the TNI. These
- "network component" evaluations allocate basic requirements
- (Mandatory Access Control (MAC); Discretionary Access Control
- (DAC); Audit; and Identification and Authentication) to
- components of a "network system". Each component may be
- evaluated in isolation. The TPEP does evaluate degenerate TNI
- components that independently meet all basic requirements (but
- nevertheless have an interface to other, perhaps identical
- components), but has not evaluated any degenerate TNI component
- that met none of the basic requirements (relying totally on
- other components for the security features). The TPEP is
- currently developing a more integrated approach to the evaluation
- of TNI components. The preliminary report of the changes
- envisioned are available in postscript at
- <http://www.radium.ncsc.mil/tpep/library/process_documents/cwg-draft.ps>.
-
- 6. What is a Network Security Architecture Design (NSAD) document?
-
- The documentation for a network component (see Section III,
- Question 5) must include a Network Security Architecture Design
- (NSAD) document which describes the security expectations by this
- component about other components. Each component evaluation
- proceeds under the assumption that the expectations of the NSAD
- are met by the other components. A collection of components
- designed around the same architecture should interoperate
- securely.
-
- 7. How do I interpret a rating?
-
- A product evaluated by the Trusted Product Evaluation Program
- (TPEP) will have one of several styles of ratings. A product
- evaluated against the Trusted Computer System Evaluation
- Criteria (TCSEC) will have one of the seven class ratings: A1,
- B3, B2, B1, C2, C1, or D (see Section III, Question 4.) In
- addition a TCSEC evaluated product may be evaluated to have met
- requirements above it's class. These would be specified
- additionally such as "meets the B1 requirements and the B2
- Trusted Path requirement." It is very important to note that,
- for example, a B1 evaluated system with B2 trusted path,
- provides significantly less confidence that trusted path is
- implemented correctly than a B2 evaluated system. That is to
- say that the assurance is always that of the system's rated
- class.
-
- Some systems have been evaluated against the Compartmented Mode
- Workstation (CMW) criteria. The CMW criteria levies minimum
- features and assurances from the TCSEC as well as additional
- usability criteria (e.g., specifying that the window system must
- manipulate windows at multiple levels in certain ways.) The
- TPEP has treated these systems as standard TCSEC evaluations
- with additional requirements. From a security perspective the
- CMW requirements do not preclude a B2 or higher CMW, however,
- to this point all CMW evaluated systems are B1 evaluated with
- additional TCSEC features above the evaluated class.
-
- Another form of rating is a Trusted Network Interpretation
- (TNI) component (see Section III, Question 5) rating. TNI
- component ratings specify the evaluated class as well as which
- of the four basic security services the evaluated component
- provides. Thus, a B2-MD component is one that provides both
- Mandatory Access Control (MAC) and Discretionary Access Control
- (DAC). A B1-MDIA component is one that provides MAC, DAC,
- Identification and Authentication, and Audit. Since a B1-MDIA
- component meets all the Trusted Computer System Evaluation
- Criteria (TCSEC) requirements for B1, it is likely that this
- component is also evaluated as a B1 system if it can be used in
- a non-network configuration.
-
- A third form of rating is a Trusted Database Interpretation
- (TDI) rating. This rating is the same as a TCSEC rating except
- that the rating applies to the composite of the evaluated
- application and each of the listed underlying systems.
-
- Finally, products evaluated against the Computer Security
- Subsystem Interpretation (CSSI) of the TCSEC have been given
- variations of D division (see Question 4) ratings. These
- appear for example as I&A/D2, Audit/D1, DAC/D3, and OR/D.
- These products all have very low assurance regardless of the
- features.
-
- 8. The TCSEC is 10 years old, doesn't that mean it's outdated?
-
- The Trusted Computer System Evaluation Criteria (TCSEC) was
- published in 1985. While some of the details need
- interpretation for current systems, in general the requirements
- of the TCSEC are at a level of abstraction that has not
- experienced great change. For the areas where it is becoming
- difficult to use the TCSEC, the Common Criteria (see Section
- II, Question 8) should provide more relevant criteria.
-
- 9. How do the TCSEC and its interpretations apply to routers and
- firewalls?
-
- The Trusted Network Interpretation (TNI) of the TCSEC has been
- used to evaluate these types of products. While there is some
- value to those evaluations it is true that many of the specific
- mechanisms of these products on which one might wish to have an
- evaluator comment are not recognized by the TNI. It is hoped
- that the Common Criteria (see Section II, Question 8) will be
- able to address these products more directly with, for example,
- an appropriate profile.
-
- 10. Does a trusted system require custom hardware?
-
- A system does not require custom hardware to be successfully
- evaluated against the Trusted Computer System Evaluation
- Criteria (TCSEC). However, an evaluation does consider the
- security of the system hardware as well as software. For every
- evaluated product, there is an evaluated configuration. The
- evaluated configuration lists the specific hardware and
- software evaluated. A given evaluation may require hardware
- with certain security features used by the software, and the
- software may require certain optional features be enabled or
- disabled. The Final Evaluation Report (FER) (see Section V,
- Question 7) lists the evaluated hardware and software. The
- Trusted Facility Manual (TFM) for the product will give
- detailed guidance on configuring the hardware and software
- securely.
-
- 11. What are the requirements for a D/C1/C2/B1/B2/B3/A1 system?
-
- The Interpreted Trusted Computer System Evaluation Criteria
- (ITCSEC) available in postscript at
- <http://www.radium.ncsc.mil/tpep/library/tcsec/ITCSEC.ps>
- contains the definitive set of requirements for each TCSEC
- class. In Summary:
-
- Class D: Minimal Protection
-
- Class D is reserved for those systems that have been evaluated
- but that fail to meet the requirements for a higher evaluation
- class.
-
- Class C1: Discretionary Security Protection
-
- The Trusted Computing Base (TCB) of a class C1 system
- nominally satisfies the discretionary security requirements by
- providing separation of users and data. It incorporates some
- form of credible controls capable of enforcing access
- limitations on an individual basis, i.e., ostensibly suitable
- for allowing users to be able to protect project or private
- information and to keep other users from accidentally reading
- or destroying their data. The class C1 environment is
- expected to be one of cooperating users processing data at the
- same level of sensitivity.
-
- Class C2: Controlled Access Protection
-
- Systems in this class enforce a more finely grained
- discretionary access control than C1 systems, making users
- individually accountable for their actions through login
- procedures, auditing of security-relevant events, and resource
- isolation.
-
- Class B1: Labeled Security Protection
-
- Class B1 systems require all the features required for class
- C2. In addition, an informal statement of the security policy
- model, data labeling (e.g., secret or proprietary), and
- mandatory access control over named subjects and objects must
- be present. The capability must exist for accurately labeling
- exported information.
-
- Class B2: Structured Protection
-
- In class B2 systems, the TCB is based on a clearly defined and
- documented formal security policy model that requires the
- discretionary and mandatory access control enforcement found
- in class B1 systems be extended to all subjects and objects in
- the automated data processing system. In addition, covert
- channels are addressed. The TCB must be carefully structured
- into protection-critical and non- protection-critical
- elements. The TCB interface is well-defined and the TCB
- design and implementation enable it to be subjected to more
- thorough testing and more complete review. Authentication
- mechanisms are strengthened, trusted facility management is
- provided in the form of support for system administrator and
- operator functions, and stringent configuration management
- controls are imposed. The system is relatively resistant to
- penetration.
-
- Class B3: Security Domains
-
- The class B3 TCB must satisfy the reference monitor
- requirements that it mediate all accesses of subjects to
- objects, be tamperproof, and be small enough to be subjected
- to analysis and tests. To this end, the TCB is structured to
- exclude code not essential to security policy enforcement,
- with significant system engineering during TCB design and
- implementation directed toward minimizing its complexity. A
- security administrator is supported, audit mechanisms are
- expanded to signal security-relevant events, and system
- recovery procedures are required. The system is highly
- resistant to penetration.
-
- Class A1: Verified Design
-
- Systems in class A1 are functionally equivalent to those in
- class B3 in that no additional architectural features or
- policy requirements are added. The distinguishing feature of
- systems in this class is the analysis derived from formal
- design specification and verification techniques and the
- resulting high degree of assurance that the TCB is correctly
- implemented. This assurance is developmental in nature,
- starting with a formal model of the security policy and a
- formal top-level specification (FTLS) of the design. An FTLS
- is a top level specification of the system written in a
- formal mathematical language to allow theorems (showing the
- coorespondence of the system specification to its formal
- requirements) to be hypothesized and formally proven. In
- keeping with the extensive design and development analysis of
- the TCB required of systems in class A1, more stringent
- configuration management is required and procedures are
- established for securely distributing the system to sites. A
- system security administrator is supported.
-
- ----------
-
- Subject: Section IV: Evaluations
-
- 1. How do I get my product evaluated?
-
- Product developers who have a product that they wish to have
- evaluated need to request a proposal package from:
-
- V24, TRUSTED PRODUCT EVALUATION PROGRAM
- NATIONAL SECURITY AGENCY
- 9800 SAVAGE ROAD STE 6740
- FT MEADE MD 20755-6740
-
- The ultimate proposal for product evaluation will include
- technical and marketing details for the product. Because the
- Trusted Product Evaluation Program (TPEP) is legislatively
- prohibited from directly evaluating products that are not
- intended to protect classified information, the proposal
- marketing information should include details about the market
- potential within the United States Department of Defense and
- intelligence communities. Additionally, the TPEP in general
- does not accept products targeting the C1 and below evaluation
- classes, as these are usually inappropriate for processing any
- classified information. TPEP currently accepts for evaluation
- at the C2 and higher levels, networked systems which meet the
- market and technical criteria. The product technical details
- will include descriptions of the product's documentation and how
- that documentation's structure compares to that required by the
- PGWG documents (see Section II, Question 11). Finally, the
- proposed configuration of the product should be a configuration
- likely to be used by the described potential market.
-
- 2. What is the evaluation process?
-
- The evaluation process is described in detail at
- <http://www.radium.ncsc.mil/tpep/process/procedures.html> In
- general terms, a successful evaluation proceeds through the
- following stages:
-
- Proposal Review
-
- A product proposal, submitted by a vendor for consideration of
- evaluation by TPEP is reviewed for two purposes. The first is
- to determine the potential market benefits of accepting the
- product for evaluation (i.e., the DoD customer base). The
- market analysis is performed based upon both the vendor's proposal
- and upon TPEP customer input, which is actively solicited on a
- regular basis. The second part of the proposal review is to
- determine, at a very preliminary level, if the product appears
- to provide feasible security mechanisms such that the requirements
- of the TCSEC can be satisfied. Once the review of the product
- proposal is completed, the vendor is notified in writing of the
- acceptance or rejection of the product for evaluation.
-
- Technical Assessment
-
- Products whose proposals were recommended as "accept" are
- considered candidates for evaluation and proceed to the next
- step in pre-evaluation, the Technical Assessment (TA), where
- a vendor must demonstrate that the product design and the
- associated evaluation evidence are complete. A TA is often
- the first examination of the product and the evidence by a
- technical evaluation team. Vendors may have excellent and
- complete documentation, indicating a readiness to undergo an
- Intensive Preliminary Technical Review (IPTR) which is the
- gateway to evaluation when successfully completed. Advice may
- be recommended based on readiness.
-
- Advice
-
- The purpose of advice is to aid the vendor in producing a product
- and supporting documentation that is capable of being evaluated
- against the TCSEC and its interpretations. Advice can be provided
- by contractors outside of TPEP or TPEP evaluators may be assigned
- to advise the vendor. TPEP-provided advice begins after a vendor
- has submitted a proposal and a technical assessment has been
- performed that deemed the product suitable for evaluation, but
- not yet ready for an IPTR.
-
- Intensive Preliminary Technical Review (IPTR)
-
- The IPTR is an independent assessment by the TPEP evaluators to
- determine a product's readiness for evaluation. An IPTR lasts
- for approximately 7-10 days and is performed by a team of
- approximately 5 TPEP evaluators. During the IPTR, which is
- usually held at the vendor's site, the team becomes familiar with
- the product (through vendor presentations); reviews documentation,
- test plans, and procedures; and documents its findings in a report.
- The IPTR report is provided to the vendor and TPEP management and
- documents the team's assessment of the product's readiness for
- evaluation. Completion of a successful IPTR results in the
- product moving into evaluation (pending availability of TPEP
- evaluation resources).
-
- Evaluation
-
- Evaluation is the comprehensive technical analysis of a product's
- security functionality. At the beginning of evaluation, the
- vendor provides the evaluation team with system level, developer-
- oriented training for the product. Training is followed by
- analysis of the product design, focusing specifically on security
- features. This analysis includes both hardware and software
- components of the product and associated documentation. Testing
- of the product involves running the vendor's test suite, as well
- as tests formulated by the evaluation team. Upon successful
- completion of testing and rigorous technical reviews by senior
- members of the evaluation community, the product is awarded an
- Evaluated Products List (EPL) entry.
-
- Rating Maintenance Phase (RAMP)
-
- RAMP provides a mechanism for a vendor to maintain the TCSEC
- rating of a product throughout its life cycle. During RAMP,
- the vendor works with the TPEP assigned Technical Point of
- Contact (TPOC) to analyze the security impact of proposed changes
- to the evaluated product. The Vendor Security Analyst (VSA)
- actually performs the security analysis of the product changes
- as they occur. The changes and associated analysis results are
- presented to a TPEP Technical Review Board (TRB) which recommends
- approval (or disapproval) of the rating for the "new" product.
-
- 3. How long does an evaluation take?
-
- The length of time a developer needs to prepare for an
- Intensive Preliminary Technical Review (IPTR) varies
- considerably. The IPTR is a short (one to two week) assessment
- of the state of the product documentation and testing. A
- successfull IPTR ensures that the materials needed for
- evaluation are complete and usable. Currently, we expect
- successful evaluations at the C2/B1 class to take approximately
- one year to complete from successful IPTR to final technical
- review. IPTRs should ideally take place approximately eight
- months before product release for a typical C2/B1 product, and
- even earlier in the product cycle for products targeted at B2,
- B3 or A1. We continue to explore ways to reduce the time
- required. Higher class evaluations take longer, although this
- is somewhat mitigated by the fact that the TPEP is usually
- involved earlier in the design process for systems at
- relatively higher classes. Problems during evaluation, changes
- in the configuration the vendor is planning to market, and
- system complexity can all add to the length of evaluation.
- Vendors participating in the RAMP (Rating Maintenance) process
- can perform analysis of changes to an already evaluated system
- to maintain the evaluated rating on subsequent versions and
- configurations. The length of time to obtain a RAMP rating is
- largely dependent on the vendor and on the nature and
- complexity of the change. However, it is reasonable to expect
- this RAMP to take far less time than an evaluation.
-
- 4. How much does an evaluation cost?
-
- The Trusted Product Evaluation Program (TPEP) does not charge
- for evaluations. It may be a significant expense for a product
- developer to prepare for and support evaluation. There are
- often travel expenses for staff, training costs for the
- evaluation team, and the cost of having development personnel
- take time to respond to the evaluation team's questions. In
- addition, if the product did not previously meet the
- requirements for a given class, the cost of improving the
- product (i.e., doing the testing, analysis and documentation)
- can be high. Ultimately, this should result in an improved
- product that will be recognized as superior to competitors.
-
- 5. How do I find out about the evaluation process?
-
- For an abstract view of the evaluation process you can read
- this list of Frequently Answered Questions (FAQ)! For a more
- detailed view appropriate to those who wish to participate in
- the process, the process is described in some detail at
- <http://www.radium.ncsc.mil/tpep/process/procedures.html>.
-
- 6. Who actually performs the evaluations?
-
- Trusted product evaluators come from the Trusted Product
- Evaluation Program (TPEP) organization within the National
- Security Agency (NSA) as well as from a small group of federal
- contract research organizations. Some evaluations have also
- benefitted from the participation of evaluators from the
- security evaluation organizations of other cooperating
- governments. In cooperation with the National Institute of
- Standards and Technology (NIST), a program is being developed to
- evaluate products in the lower Trusted Computer System
- Evaluation Criteria (TCSEC) classes (i.e., C2/B1) using
- approved commercial evaluation facilities. However, many
- details remain to be finalized for that program.
-
- 7. What information is released about an evaluated product?
-
- As we begin working with a product, the vendor and target
- rating are made available. When that product is accepted into
- evaluation, information such as the vendor, target rating, and
- target completion date are announced in a product announcement
- on the Evaluated Products List (EPL) (see Section V, Question
- 6). When the evaluation is completed the general evaluated
- product configuration, general product information, and rating
- are announced in an entry on the EPL. In addition at the
- completion of evaluation a report is published (see Section V,
- Question 7). This report contains the analysis of the
- evaluation team, a complete description of the evaluated
- product, and often comments about the usability of the product
- in its evaluated configuration by the evaluation team. Recent
- EPL entries and a few Final Evaluation Reports are available at
- <http://www.radium.ncsc.mil/tpep/epl/>.
-
-
- 8. What is RAMP?
-
- The Rating Maintenance Phase (RAMP) Program was established to
- provide a mechanism to extend the previous rating to a new
- version of a previously evaluated computer system product.
- RAMP seeks to reduce evaluation time and effort required to
- maintain a rating by using the personnel involved in the
- maintenance of the product to manage the change process and
- perform Security Analysis. Thus, the burden of proof for RAMP
- efforts lies with those responsible for system maintenance
- (i.e., the vendor) instead of with an evaluation team.
-
- ----------
-
- Subject: Section V: Evaluated Products
-
- 1. Should I buy an evaluated product?
-
- An evaluated product has the benefit of providing an
- independent assessment that the product meets the criteria for
- the rating it achieved. When considering a specific
- installation the value of the data and the threat to that data
- both need to be considered. These are often related, in that
- more valuable data has a higher threat. If some of the threats
- to the data can be countered by the features or assurance of a
- trusted product, then it is certainly worthwhile to consider
- that in your purchase decision. All other things being equal
- (which is rarely the case) the independent assessment of an
- evaluated product adds value.
-
- 2. Does NSA buy/use evaluated products?
-
- NSA endevours to be an exemplary customer of the products it
- recommends for use by its customers and expects NSA-evaluated
- products to comprise the foundation of its own secure information
- systems architecture and is developing policy towards that end.
-
- 3. How do I know if a product is evaluated?
-
- The simplest way to find out if a product is not evaluated is
- to ask the product vendor. If the vendor has an evaluated
- product, it is a pretty good bet that the company marketing
- people are aware of it. Many products that have NOT been
- evaluated have names containing a rating or have declared
- themselves as "designed to meet" a specific rating. These products
- have not withstood the same scrutiny as products listed on the EPL.
-
- If a vendor claims to have an evaluated product, you should
- independently verify the details of the evaluation (e.g.,
- product version, configuration, rating.) All evaluated products
- are placed on the Evaluated Products List (EPL) (see Section V,
- Question 6). That is the first place to look. The EPL entries
- that have been awarded within the last three years are available
- at <http://www.radium.ncsc.mil/tpep/epl/>. To verify a specific
- detail (e.g., the rating) of an evaluation, you may call the Trusted
- Product Evaluation Program (TPEP) directly at (410) 859-4458 This
- will often result in less complete information since generally we
- don't read entire EPL entries over the phone.
-
- For the most complete information about a specific evaluated
- product, you should request a copy of the evaluation report.
- (see Section V, Question 7) Unfortunately, the publication of
- the report sometimes postdates the evaluation significantly.
- An increasing number of final evaluation reports are available
- via links from the product's electronic EPL entry or from
- <http://www.radium.ncsc.mil/tpep/library/fers/> by report number.
-
- 4. What does it mean for a product to be "in evaluation"?
-
- In the past it has been the case that Trusted Product
- Evaluation Program (TPEP) evaluations where conducted over
- longer periods of time and included time for a developer to
- work out problems with their documentation and testing that a
- current Intensive Preliminary Architecture Review (IPTR) is
- designed to limit. Currently a product is not announced to be
- in evaluation until it has successfully passed an IPTR. Even
- so, a product may go through several releases, incorporate
- fixes during the course of evaluation, or even potentially drop
- out of evaluation or fail evaluation. Because of this a
- product in evaluation is not equivalent to an evaluated
- product. While it does show some intent to have an evaluated
- product, and a consideration of security criteria in the
- product development, it does not necessarily imply any security
- features or assurances. Buyers of products in evaluation
- should consider what options will be available to them should
- the evaluated configuration differ significantly from the
- purchased configuration, or if the product does not ultimately
- complete evaluation.
-
- 5. What does it mean for a product to be "compliant" with the TCSEC?
-
- If a product has been evaluated by the Trusted Product
- Evaluation Program (TPEP) to comply with the requirements of a
- rated class, then it means that an independent assessment
- showed the product to have the features and assurances of that
- class. It does not mean that the product is impenetrable. It
- is even possible that the independent assessment overlooked
- some failure to meet the criteria, although we expend a lot of
- energy attempting to prevent that. A vendor claim to be
- "compliant" without an evaluation often doesn't mean very much
- since the vendor's interpretation of the requirement may not be
- the same as an independent assessor's would be.
-
- 6. What and where is the Evaluated Products List (EPL)?
-
- The Evaluated Products List (EPL) officially is published
- quarterly in the INFOSEC Products and Services Catalog (as a
- chapter). The INFOSEC Products and Services Catalog is
- available from the Government Printing Office. The EPL is also
- maintained electronically on Dockmaster and updated as new
- products are announced. (see Section I, Question 7) There is no
- anonymous access to Dockmaster so this is available only to
- Dockmaster users. EPL entries issued within the last three years
- are available at <http://www.radium.ncsc.mil/tpep/epl/>.
-
- 7. How do I get a copy of an evaluation report?
-
- Single copies of evaluation reports are available without charge
- by writing:
-
- INFOSEC AWARENESS, ATTN: Y13/IAOC
- DEPARTMENT OF DEFENSE
- 9800 SAVAGE ROAD
- FT MEADE MD 20755-6000
-
- Multiple copies are available from the Government Printing
- Office. In either case you will need the report number
- (CSC-EPL-xx/xxx or CSC-FER-xx/xxx) which is given in the
- Evaluated Products List (EPL) entry for the product. (see
- Section V, Question 6)
-
- 8. Is an evaluated product "hacker proof?"
-
- No product can be guaranteed to be "hacker proof" or
- "impenetrable." An evaluated product has demonstrated certain
- features and assurances, as specified by the rating criteria.
- Those features and assurances counter certain threats. Thus an
- evaluated product is usually vulnerable to fewer threats than
- an unevaluated product. Products with higher ratings are
- vulnerable to fewer threats than products with low ratings.
- Vulnerabilities to threats that remain in products can often be
- addressed through other means. No rating class used by the
- Trusted Product Evaluation Program (TPEP), for example,
- counters the threat of directly tampering with the hardware.
- That threat would need to be addressed physically or
- procedurally if it was realistic for the particular system
- environment.
-
- Finally, it seems many "hackers" today prefer to use "social
- engineering" to accomplish their goals. As with other
- insider-related threats, education is necessary in preventing
- naive users from disclosing sensitive information. However,
- technical measures can also help. They can enforce the the
- principle of least privilege, check the reasonableness of
- administrative inputs, and provide timely on-line cautions.
-
- 9. What is the rating of DOS?
-
- MS-DOS, PC-DOS, and DR-DOS have not been evaluated. Without
- modification, it is apparent from the most cursory examination
- that they do not implement many of the features required by the
- C1 class of the Trusted Computer System Evaluation Criteria
- (TCSEC). Several vendors support a DOS application interface
- in products designed to achieve higher class ratings.
-
- 10. What is the rating of UNIX?
-
- There are a number of evaluated products conforming to one or
- another of the UNIX interface standards (see Section V,
- Question 3). These products range from class C2 to class B3.
- In general, unevaluated UNIX products lack several features,
- including sufficient auditing, to achieve anything other than a
- D class rating without some modification.
-
- 11. What should I do if evaluated Product X appears to fail a requirement?
-
- If an evaluated product does not seem to meet the requirements,
- the first thing to do is carefully look at the Final Evaluation
- Report (FER) and the product's Trusted Facility Manual (TFM).
- The product was evaluated with specific configuration options and
- on specific hardware. These should be stated in the TFM and FER
- respectively. If the evaluated configuration still seems to not
- meet some requirement for its rated class, then it is possible that
- there was an oversight during the evaluation. You can send that
- information to tpep@dockmaster.ncsc.mil and we may investigate the
- issue.
-
- 12. Why should I buy a B2/B3/A1 product over a C2/B1 product?
-
- While the features and assurances of each class increase, the
- increase is not linear. B1 and below rated products provide a
- basic set of security features and an independent assesment that
- those features are implemented correctly. At B2 and above there
- is significantly more effort and analysis both in development and
- in evaluation that the features are correctly implemented. The
- additional development effort often translates into increased cost
- for the product. For applications involving sensitive data, the
- added cost may be well worth the added protection.
-
- 13. Is there an approved program to declassify my hard drive?
-
- In summary, no; in general, overwriting may be sufficient to have
- media released for other use, but it must retain its original
- classification.
-
- You should contact your security officer or contracts manager for
- official guidance. Often, your contract will determine how to
- declassify disks. This is usually indirect, by referencing a
- DOD-STD or other document. Be prepared to submit the disk drive
- (or at least the little metal thingy with the iron oxide) for total
- destruction.
-
- If you need to retrieve unclassified data that reside on a
- classified disk, there are often detailed procedures to accomplish
- this.
-
-
-