Common Criteria

The Common Criteria for Information Technology Security Evaluation (referred to as Common Criteria or CC) is an international standard (ISO/IEC 15408) for computer security certification. It is currently in version 3.1 revision 5.[1]

Common Criteria is a framework in which computer system users can specify their security functional and assurance requirements (SFRs and SARs respectively) in a Security Target (ST), and may be taken from Protection Profiles (PPs). Vendors can then implement 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 and repeatable manner at a level that is commensurate with the target environment for use.[2]

Key concepts

Common Criteria evaluations are performed on computer security products and systems.

  • Target of Evaluation (TOE) – the product or system that is the subject of the evaluation. The evaluation serves to validate claims made about the target. To be of practical use, the evaluation must verify the target's security features. This is done through the following:
    • Protection Profile (PP) – a document, typically created by a user or user community, which identifies security requirements for a class of security devices (for example, smart cards used to provide digital signatures, or network firewalls) relevant to that user for a particular purpose. Product vendors can choose to implement products that comply with one or more PPs, and have their products evaluated against those PPs. In such a case, a PP may serve as a template for the product's ST (Security Target, as defined below), or the authors of the ST will at least ensure that all requirements in relevant PPs also appear in the target's ST document. Customers looking for particular types of products can focus on those certified against the PP that meets their requirements.
    • Security Target (ST) – the document that identifies the security properties of the target of evaluation. The ST may claim conformance with one or more PPs. The TOE is evaluated against the SFRs (Security Functional Requirements. Again, see below) established in its ST, no more and no less. This allows vendors to tailor the evaluation to accurately match the intended capabilities of their product. This means that a network firewall does not have to meet the same functional requirements as a database management system, and that different firewalls may in fact be evaluated against completely different lists of requirements. The ST is usually published so that potential customers may determine the specific security features that have been certified by the evaluation.
    • Security Functional Requirements (SFRs) – specify individual security functions which may be provided by a product. The Common Criteria presents a standard catalogue of such functions. For example, a SFR may state how a user acting a particular role might be authenticated. The list of SFRs can vary from one evaluation to the next, even if two targets are the same type of product. Although Common Criteria does not prescribe any SFRs to be included in an ST, it identifies dependencies where the correct operation of one function (such as the ability to limit access according to roles) is dependent on another (such as the ability to identify individual roles).

The evaluation process also tries to establish the level of confidence that may be placed in the product's security features through quality assurance processes:

  • Security Assurance Requirements (SARs) – descriptions of the measures taken during development and evaluation of the product to assure compliance with the claimed security functionality. For example, an evaluation may require that all source code is kept in a change management system, or that full functional testing is performed. The Common Criteria provides a catalogue of these, and the requirements may vary from one evaluation to the next. The requirements for particular targets or types of products are documented in the ST and PP, respectively.
  • Evaluation Assurance Level (EAL) – the numerical rating describing the depth and rigor of an evaluation. Each EAL corresponds to a package of security assurance requirements (SARs, see above) which covers the complete development of a product, with a given level of strictness. Common Criteria lists seven levels, with EAL 1 being the most basic (and therefore cheapest to implement and evaluate) and EAL 7 being the most stringent (and most expensive). Normally, an ST or PP author will not select assurance requirements individually but choose one of these packages, possibly 'augmenting' requirements in a few areas with requirements from a higher level. Higher EALs do not necessarily imply "better security", they only mean that the claimed security assurance of the TOE has been more extensively verified.

So far, most PPs and most evaluated STs/certified products have been for IT components (e.g., firewalls, operating systems, smart cards). Common Criteria certification is sometimes specified for IT procurement. Other standards containing, e.g., interoperation, system management, user training, supplement CC and other product standards. Examples include the ISO/IEC 17799 (Or more properly BS 7799-1, which is now ISO/IEC 27002) or the German IT-Grundschutzhandbuch.

Details of cryptographic implementation within the TOE are outside the scope of the CC. Instead, national standards, like FIPS 140-2 give the specifications for cryptographic modules, and various standards specify the cryptographic algorithms in use.

More recently, PP authors are including cryptographic requirements for CC evaluations that would typically be covered by FIPS 140-2 evaluations, broadening the bounds of the CC through scheme-specific interpretations.

Some national evaluation schemes are phasing out EAL-based evaluations and only accept products for evaluation that claim strict conformance with an approved PP. The United States currently only allows PP-based evaluations. Canada is in the process of phasing out EAL-based evaluations.


CC originated out of three standards:

  • ITSEC – The European standard, developed in the early 1990s by France, Germany, the Netherlands and the UK. It too was a unification of earlier work, such as the two UK approaches (the CESG UK Evaluation Scheme aimed at the defence/intelligence market and the DTI Green Book aimed at commercial use), and was adopted by some other countries, e.g. Australia.
  • CTCPEC – The Canadian standard followed from the US DoD standard, but avoided several problems and was used jointly by evaluators from both the U.S. and Canada. The CTCPEC standard was first published in May 1993.
  • TCSEC – The United States Department of Defense DoD 5200.28 Std, called the Orange Book and parts of the Rainbow Series. The Orange Book originated from Computer Security work including the Anderson Report, done by the National Security Agency and the National Bureau of Standards (the NBS eventually became NIST) in the late 1970s and early 1980s. The central thesis of the Orange Book follows from the work done by Dave Bell and Len LaPadula for a set of protection mechanisms.

CC was produced by unifying these pre-existing standards, predominantly so that companies selling computer products for the government market (mainly for Defence or Intelligence use) would only need to have them evaluated against one set of standards. The CC was developed by the governments of Canada, France, Germany, the Netherlands, the UK, and the U.S.

Testing organizations

All testing laboratories must comply with ISO 17025, and certification bodies will normally be approved against either ISO/IEC Guide 65 or BS EN 45011.

The compliance with ISO 17025 is typically demonstrated to a National approval authority:

Characteristics of these organizations were examined and presented at ICCC 10.[3]

Mutual recognition arrangement

As well as the Common Criteria standard, there is also a sub-treaty level Common Criteria MRA (Mutual Recognition Arrangement), whereby each party thereto recognizes evaluations against the Common Criteria standard done by other parties. Originally signed in 1998 by Canada, France, Germany, the United Kingdom and the United States, Australia and New Zealand joined 1999, followed by Finland, Greece, Israel, Italy, the Netherlands, Norway and Spain in 2000. The Arrangement has since been renamed Common Criteria Recognition Arrangement (CCRA) and membership continues to expand. Within the CCRA only evaluations up to EAL 2 are mutually recognized (Including augmentation with flaw remediation). The European countries within the former ITSEC agreement typically recognize higher EALs as well. Evaluations at EAL5 and above tend to involve the security requirements of the host nation's government.

In September 2012, a majority of members of the CCRA produced a vision statement whereby mutual recognition of CC evaluated products will be lowered to EAL 2 (Including augmentation with flaw remediation). Further, this vision indicates a move away from assurance levels altogether and evaluations will be confined to conformance with Protection Profiles that have no stated assurance level. This will be achieved through technical working groups developing worldwide PPs, and as yet a transition period has not been fully determined.

On July 2, 2014, a new CCRA was ratified per the goals outlined within the 2012 vision statement. Major changes to the Arrangement include:

  • Recognition of evaluations against only a collaborative Protection Profile (cPP) or Evaluation Assurance Levels 1 through 2 and ALC_FLR.
  • The emergence of international Technical Communities (iTC), groups of technical experts charged with the creation of cPPs.
  • A transition plan from the previous CCRA, including recognition of certificates issued under the previous version of the Arrangement.



Common Criteria is very generic; it does not directly provide a list of product security requirements or features for specific (classes of) products: this follows the approach taken by ITSEC, but has been a source of debate to those used to the more prescriptive approach of other earlier standards such as TCSEC and FIPS 140-2.

Value of certification

Common Criteria certification cannot guarantee security, but it can ensure that claims about the security attributes of the evaluated product were independently verified. In other words, products evaluated against a Common Criteria standard exhibit a clear chain of evidence that the process of specification, implementation, and evaluation has been conducted in a rigorous and standard manner.

Various Microsoft Windows versions, including Windows Server 2003 and Windows XP, have been certified, but security patches to address security vulnerabilities are still getting published by Microsoft for these Windows systems. This is possible because the process of obtaining a Common Criteria certification allows a vendor to restrict the analysis to certain security features and to make certain assumptions about the operating environment and the strength of threats faced by the product in that environment. Additionally, the CC recognizes a need to limit the scope of evaluation in order to provide cost-effective and useful security certifications, such that evaluated products are examined to a level of detail specified by the assurance level or PP. Evaluations activities are therefore only performed to a certain depth, use of time, and resources and offer reasonable assurance for the intended environment.

In the Microsoft case, the assumptions include A.PEER:

"Any other systems with which the TOE communicates are assumed to be under the same management control and operate under the same security policy constraints. The TOE is applicable to networked or distributed environments only if the entire network operates under the same constraints and resides within a single management domain. There are no security requirements that address the need to trust external systems or the communications links to such systems."

This assumption is contained in the Controlled Access Protection Profile (CAPP) to which their products adhere. Based on this and other assumptions, which may not be realistic for the common use of general-purpose operating systems, the claimed security functions of the Windows products are evaluated. Thus they should only be considered secure in the assumed, specified circumstances, also known as the evaluated configuration.

Whether you run Microsoft Windows in the precise evaluated configuration or not, you should apply Microsoft's security patches for the vulnerabilities in Windows as they continue to appear. If any of these security vulnerabilities are exploitable in the product's evaluated configuration, the product's Common Criteria certification should be voluntarily withdrawn by the vendor. Alternatively, the vendor should re-evaluate the product to include the application of patches to fix the security vulnerabilities within the evaluated configuration. Failure by the vendor to take either of these steps would result in involuntary withdrawal of the product's certification by the certification body of the country in which the product was evaluated.

The certified Microsoft Windows versions remain at EAL4+ without including the application of any Microsoft security vulnerability patches in their evaluated configuration. This shows both the limitation and strength of an evaluated configuration.


In August 2007, Government Computing News (GCN) columnist William Jackson critically examined Common Criteria methodology and its US implementation by the Common Criteria Evaluation and Validation Scheme (CCEVS).[4] In the column executives from the security industry, researchers, and representatives from the National Information Assurance Partnership (NIAP) were interviewed. Objections outlined in the article include:

  • Evaluation is a costly process (often measured in hundreds of thousands of US dollars) – and the vendor's return on that investment is not necessarily a more secure product.
  • Evaluation focuses primarily on assessing the evaluation documentation, not on the actual security, technical correctness or merits of the product itself. For U.S. evaluations, only at EAL5 and higher do experts from the National Security Agency participate in the analysis; and only at EAL7 is full source code analysis required.
  • The effort and time necessary to prepare evaluation evidence and other evaluation-related documentation is so cumbersome that by the time the work is completed, the product in evaluation is generally obsolete.
  • Industry input, including that from organizations such as the Common Criteria Vendor's Forum, generally has little impact on the process as a whole.

In a 2006 research paper, computer specialist David A. Wheeler suggested that the Common Criteria process discriminates against free and open-source software (FOSS)-centric organizations and development models.[5] Common Criteria assurance requirements tend to be inspired by the traditional waterfall software development methodology. In contrast, much FOSS software is produced using modern agile paradigms. Although some have argued that both paradigms do not align well,[6] others have attempted to reconcile both paradigms.[7] Political scientist Jan Kallberg raised concerns over the lack of control over the actual production of the products once they are certified, the absence of a permanently staffed organizational body that monitors compliance, and the idea that the trust in the Common Criteria IT-security certifications will be maintained across geopolitical boundaries.[8]

Alternative approaches

Throughout the lifetime of CC, it has not been universally adopted even by the creator nations, with, in particular, cryptographic approvals being handled separately, such as by the Canadian / US implementation of FIPS-140, and the CESG Assisted Products Scheme (CAPS)[9] in the UK.

The UK has also produced a number of alternative schemes when the timescales, costs and overheads of mutual recognition have been found to be impeding the operation of the market:

  • The CESG System Evaluation (SYSn) and Fast Track Approach (FTA) schemes for assurance of government systems rather than generic products and services, which have now been merged into the CESG Tailored Assurance Service (CTAS) [10]
  • The CESG Claims Tested Mark (CCT Mark), which is aimed at handling less exhaustive assurance requirements for products and services in a cost and time efficient manner

In early 2011, NSA/CSS published a paper by Chris Salter, which proposed a Protection Profile oriented approach towards evaluation. In this approach, communities of interest form around technology types which in turn develop protection profiles that define the evaluation methodology for the technology type.[11] The objective is a more robust evaluation. There is some concern that this may have a negative impact on mutual recognition.[12]

In Sept of 2012, the Common Criteria published a Vision Statement implementing to a large extent Chris Salter's thoughts from the previous year. Key elements of the Vision included:

  • Technical Communities will be focused on authoring Protection Profiles (PP) that support their goal of reasonable, comparable, reproducible and cost-effective evaluation results
  • Evaluations should be done against these PP's if possible; if not mutual recognition of Security Target evaluations would be limited to EAL2

See also


  1. ^ "The Common Criteria".
  2. ^ "Common Criteria - Communication Security Establishment".
  3. ^ "Common Criteria Schemes Around the World" (PDF).
  4. ^ Under Attack: Common Criteria has loads of critics, but is it getting a bum rap Government Computer News, retrieved 2007-12-14
  5. ^ Free-Libre / Open Source Software (FLOSS) and Software Assurance
  6. ^ Wäyrynen, J., Bodén, M., and Boström, G., Security Engineering and eXtreme Programming: An Impossible Marriage?
  7. ^ Beznosov, Konstantin; Kruchten, Philippe. "Towards Agile Security Assurance". Retrieved 2007-12-14.
  8. ^ Common Criteria meets Realpolitik – Trust, Alliances, and Potential Betrayal
  9. ^ "CAPS: CESG Assisted Products Scheme". Archived from the original on August 1, 2008.
  10. ^ Infosec Assurance and Certification Services (IACS) Archived February 20, 2008, at the Wayback Machine
  11. ^ "Common Criteria Reforms: Better Security Products Through Increased Cooperation with Industry" (PDF). Archived from the original (PDF) on April 17, 2012.
  12. ^ "Common Criteria "Reforms"—Sink or Swim-- How should Industry Handle the Revolution Brewing with Common Criteria?".

External links

Canadian Trusted Computer Product Evaluation Criteria

The Canadian Trusted Computer Product Evaluation Criteria (CTCPEC) is a computer security standard published in 1993 by the Communications Security Establishment to provide an evaluation criterion on IT products. It is a combination of the TCSEC (also called Orange Book) and the European ITSEC approaches.

CTCPEC led to the creation of the Common Criteria standard.The Canadian System Security Centre, part of the Communications Security Establishment was founded in 1988 to establish a Canadian computer security standard.

The Centre published a draft of the standard in April 1992. The final version was published in January 1993.

Colorado Book Awards

The Colorado Book Awards are awards presented annually to Colorado authors, editors, illustrators, and photographers who exemplify the best in their category in the state during a given year. Awards have been presented since 1991. The awards are given by the Colorado Center for the Book, itself a program of Colorado Humanities. Awards are selected by a group of judges who are themselves selected on the basis of interest and competence. The common criteria for each category are content, originality, and widespread appeal; each category also has additional criteria appropriate to that category.

Common Criteria Evaluation and Validation Scheme

Common Criteria Evaluation and Validation Scheme (CCEVS) is a United States Government program administered by the National Information Assurance Partnership (NIAP) to evaluate security functionality of an information technology with conformance to the Common Criteria international standard. The new standard uses Protection Profiles and the Common Criteria Standards to certify the product. This change happened in 2009. The change was implemented to bring credibility back to the CC brand. Their stated goal in making the change was to ensure achievable, repeatable and testable evaluations.

Common Criteria Testing Laboratory

The Common Criteria model provides for the separation of the roles of evaluator and certifier. Product certificates are awarded by national schemes on the basis of evaluations carried by independent testing laboratories.

A Common Criteria testing laboratory is a third-party commercial security testing facility that is accredited to conduct security evaluations for conformance to the Common Criteria international standard. Such facility must be accredited according to ISO/IEC 17025 with its national certification body.

Cryptographic Module Testing Laboratory

A Cryptographic Module Testing Laboratory (CMTL) is an information technology (IT) computer security testing laboratory that is accredited to conduct cryptographic module evaluations for conformance to the FIPS 140-2 U.S. Government standard.

The National Institute of Standards and Technology (NIST) National Voluntary Laboratory Accreditation Program (NVLAP) accredits CMTLs to meet Cryptographic Module Validation Program (CMVP) standards and procedures.

This has been replaced by FIPS 140-2 and the Cryptographic Module Validation Program (CMVP).


Cyberoam Technologies, a Sophos Company, is a global Network Security appliances provider, with presence in more than 125 countries. The company offers User Identity-based network security in its Firewalls/ Unified Threat Management appliances, allowing visibility and granular control into users' activities in business networks. For SOHO, SMB and large enterprise networks, this ensures security built around the network user for protection against APTs, insider threats, malware, hacker, and other sophisticated network attacks.

Cyberoam has sales offices in North America, EMEA and APAC. The company has its customer support and development centers in India and has 550+ employees across the globe. It has a channel-centric approach for its sales with a global network of 4500+ partners. The company also conducts training programs for its customers and partners.

Evaluation Assurance Level

The Evaluation Assurance Level (EAL1 through EAL7) of an IT product or system is a numerical grade assigned following the completion of a Common Criteria security evaluation, an international standard in effect since 1999. The increasing assurance levels reflect added assurance requirements that must be met to achieve Common Criteria certification. The intent of the higher levels is to provide higher confidence that the system's principal security features are reliably implemented. The EAL level does not measure the security of the system itself, it simply states at what level the system was tested.

To achieve a particular EAL, the computer system must meet specific assurance requirements. Most of these requirements involve design documentation, design analysis, functional testing, or penetration testing. The higher EALs involve more detailed documentation, analysis, and testing than the lower ones. Achieving a higher EAL certification generally costs more money and takes more time than achieving a lower one. The EAL number assigned to a certified system indicates that the system completed all requirements for that level.

Although every product and system must fulfill the same assurance requirements to achieve a particular level, they do not have to fulfill the same functional requirements. The functional features for each certified product are established in the Security Target document tailored for that product's evaluation. Therefore, a product with a higher EAL is not necessarily "more secure" in a particular application than one with a lower EAL, since they may have very different lists of functional features in their Security Targets. A product's fitness for a particular security application depends on how well the features listed in the product's Security Target fulfill the application's security requirements. If the Security Targets for two products both contain the necessary security features, then the higher EAL should indicate the more trustworthy product for that application.


In human anatomy, a hamstring is one of the three posterior thigh muscles in between the hip and the knee (from medial to lateral: semimembranosus, semitendinosus and biceps femoris). The hamstrings are quite susceptible to injury.

In quadrupeds, the hamstring is the single large tendon found behind the knee or comparable area.

Hardware security module

A hardware security module (HSM) is a physical computing device that safeguards and manages digital keys for strong authentication and provides cryptoprocessing. These modules traditionally come in the form of a plug-in card or an external device that attaches directly to a computer or network server.

High Assurance Guard

A High Assurance Guard (HAG) is a Multilevel security computer device which is used to communicate between different Security Domains, such as NIPRNet to SIPRNet. A HAG is one example of a Controlled Interface between security levels. HAGs are approved through the Common Criteria process.

ISO 15292

ISO 15292, "Information technology – Security techniques – Protection Profile registration procedures" establishes an international registry (operated by AFNOR) for Protection Profiles and packages used in computer security evaluation under the Common Criteria framework. The format of these profiles and packages is as specified in ISO 15408.

ISO 15292 assigns registered Protection Profiles and packages labels of the form:

"Entry Type-registration Year-registration Number", for example PP-2003-0001.

Labeled Security Protection Profile

Labeled Security Protection Profile (LSPP) is a protection profile within the Common Criteria for Information Technology Security Evaluation, a set of security functional and assurance requirements for IT products. The LSPP requirements are derived from the B1 class of the US Department of Defense security standard called Trusted Computer System Evaluation Criteria (TCSEC) which was originally published in 1985.

For example, z/OS V1.7 was certified EAL4+ for LSPP in 2006.

Multilevel security

Multilevel security or multiple levels of security (MLS) is the application of a computer system to process information with incompatible classifications (i.e., at different security levels), permit access by users with different security clearances and needs-to-know, and prevent users from obtaining access to information for which they lack authorization. There are two contexts for the use of multilevel security. One is to refer to a system that is adequate to protect itself from subversion and has robust mechanisms to separate information domains, that is, trustworthy. Another context is to refer to an application of a computer that will require the computer to be strong enough to protect itself from subversion and possess adequate mechanisms to separate information domains, that is, a system we must trust. This distinction is important because systems that need to be trusted are not necessarily trustworthy.

Noun class

In linguistics, a noun class is a particular category of nouns. A noun may belong to a given class because of the characteristic features of its referent, such as gender, animacy, shape, but counting a given noun among nouns of such or another class is often clearly conventional. Some authors use the term "grammatical gender" as a synonym of "noun class", but others use different definitions for each. Noun classes should not be confused with noun classifiers.

Protection Profile

A Protection Profile (PP) is a document used as part of the certification process according to ISO/IEC 15408 and the Common Criteria (CC). As the generic form of a Security Target (ST), it is typically created by a user or user community and provides an implementation independent specification of information assurance security requirements. A PP is a combination of threats, security objectives, assumptions, security functional requirements (SFRs), security assurance requirements (SARs) and rationales.

A PP specifies generic security evaluation criteria to substantiate vendors' claims of a given family of information system products. Among others, it typically specifies the Evaluation Assurance Level (EAL), a number 1 through 7, indicating the depth and rigor of the security evaluation, usually in the form of supporting documentation and testing, that a product meets the security requirements specified in the PP.

The National Institute of Standards and Technology (NIST) and the National Security Agency (NSA) have agreed to cooperate on the development of validated U.S. government PPs.

Security-evaluated operating system

In computing, security-evaluated operating systems have achieved certification from an external security-auditing organization, the most popular evaluations are Common Criteria (CC) and FIPS 140-2.

Solaris Trusted Extensions

Solaris Trusted Extensions is a set of security extensions incorporated in the Solaris 10 operating system by Sun Microsystems, featuring a mandatory access control model. It succeeds Trusted Solaris, a family of security-evaluated operating systems based on earlier versions of Solaris.

Solaris 10 5/09 is Common Criteria certified at Evaluation Assurance Level EAL4+ against the CAPP, RBACPP, and LSPP protection profiles.

Trusted Computer System Evaluation Criteria

Trusted Computer System Evaluation Criteria (TCSEC) is a United States Government Department of Defense (DoD) standard that sets basic requirements for assessing the effectiveness of computer security controls built into a computer system. The TCSEC was used to evaluate, classify, and select computer systems being considered for the processing, storage, and retrieval of sensitive or classified information.The TCSEC, frequently referred to as the Orange Book, is the centerpiece of the DoD Rainbow Series publications. Initially issued in 1983 by the National Computer Security Center (NCSC), an arm of the National Security Agency, and then updated in 1985, TCSEC was eventually replaced by the Common Criteria international standard, originally published in 2005.

Trusted operating system

Trusted Operating System (TOS) generally refers to an operating system that provides sufficient support for multilevel security and evidence of correctness to meet a particular set of government requirements.

The most common set of criteria for trusted operating system design is the Common Criteria combined with the Security Functional Requirements (SFRs) for Labeled Security Protection Profile (LSPP) and mandatory access control (MAC). The Common Criteria is the result of a multi-year effort by the governments of the U.S., Canada, United Kingdom, France, Germany, the Netherlands and other countries to develop a harmonized security criteria for IT products.

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