Vishnu Kesarwani

IMS2007011

MS (Cyber Law & Information Security)

IIIT-Allahabad

Introduction

Assurance Paradigm

Security Assurance Requirements

EAL Structure

Relationship Between Assurances Requirements And Assurance Levels

Assurance Categorization

Protection Profile Criteria Overview

Security Target Criteria Overview

Class APE: Protection Profile Evaluation

Class ASE: Security Target Evaluation

Evaluation Assurance Levels Evaluation Assurance Level 1 - Functionally Tested Evaluation Assurance Level 2 Structurally Tested Evaluation Assurance Level 3 Methodically Tested And Checked Evaluation Assurance Level 4 - Methodically Designed, Tested, And Reviewed Evaluation Assurance Level 5 - Semiformally Designed And Tested Evaluation Assurance Level 6 - Semiformally Verified Design And Tested Evaluation Assurance Level 7 - Formally Verified Design And Tested

Part 3 of ISO/IEC 15408

(Security Assurance Requirements)

Catalogues the set of assurance components, families and classes.

Defines evaluation criteria for Protection Profiles (PPs) and Security Targets (STs).

Presents Evaluation Assurance Levels (EALs) that define the predefined ISO/IEC 15408 (Common Criteria-CC) scale for rating assurance for Target of Evaluations (TOEs).

Audience for this part of CC Consumers, Developers, And Evaluators

of secure IT systems and products.

Defines Security Assurance Requirements: A basis for the security assurance requirements

expressed in a PP or a ST.

Establishes a standard way of expressing the assurance requirements for TOEs.

1. Philosophy

The threats to security and organizational security policy commitments should be clearly articulated

The proposed security measures should be demonstrably sufficient for their intended purpose.

Measures should be adopted that reduce the likelihood of vulnerabilities, the ability to exercise a vulnerability, and the extent of the damage that could occur from a vulnerability

being exercised facilitate the subsequent identification of vulnerabilities and

the elimination, mitigation, and/or notification that a vulnerability has been exploited or triggered.

2. Assurance Approach

assurance based upon an evaluation of the IT product or system that is to be trusted.

Assurance Through Evaluation

Evaluation techniques can includea) analysis and checking of process(es) and procedure(s);b) checking that process(es) and procedure(s) are being applied;c) analysis of the correspondence between TOE design representations;d) analysis of the TOE design representation against the requirements;e) verification of proofs;f) analysis of guidance documents;g) analysis of functional tests developed and the results provided;h) independent functional testing;i) analysis for vulnerabilities (including flaw hypothesis);j) penetration testing.

Significance of Vulnerabilities IT security breaches arise through the intentional exploitation or

the unintentional triggering of vulnerabilities in the application of IT within business concerns.

Steps to prevent vulnerabilities Eliminated Minimized Monitored

Cause of VulnerabilitiesVulnerabilities can arise through failures in:

Requirements Construction operation

3. Evaluation Assurance Scale

This scale provides:

Greater assurance

Minimum effort

Level of effort is based upon

Scope

Depth

Rigour

Protection Profile evaluation

Relation to the Security Target evaluation criteria

Evaluator tasks

Evaluator tasks for an evaluation based on CC requirements only

Evaluator tasks for an CC extended evaluation

Security Target evaluation

Relation to the other evaluation criteria in this part of CC

Evaluator tasks

Evaluator tasks for an evaluation based on CC requirements only

Evaluator tasks for a CC extended evaluation

The goal of a PP evaluation is to demonstrate that the PP is complete, consistent and technically sound.

An evaluated PP is suitable for use as the basis for the development of STs.

Such a PP is eligible for inclusion in a registry.

Objectives

Application notes

Dependencies

Developer action elements

Content and presentation of evidence elements

Evaluator action elements

The goal of an ST evaluation is to demonstrate that the ST is complete, consistent, technically sound, and suitable for use as the basis for the corresponding TOE evaluation.

Objectives

Application notes

Dependencies

Developer action elements

Content and presentation of evidence elements

Evaluator action elements

an increasing scale that balances the level of assurance obtained with the cost and feasibility of acquiring that degree of assurance.

Objectives

EAL1 is applicable where some confidence in correct operation is required, but the threats to security are not viewed as serious.

EAL1 provides an evaluation of the TOE as made available to the

customer, including independent testing against a specification, and

an examination of the guidance documentation provided.

Assurance components

EAL1 provides a basic level of assurance by an analysis of the security functions using a functional and interface specification, and guidance documentation,

to understand the security behaviour.

The analysis is supported by independent testing of the TOE security functions.

This EAL provides a meaningful increase in assurance over an unevaluated IT product or system.

Objectives

applicable in those circumstances where developers or users require a low to moderate level of independently assured security in the absence of ready availability of the complete development record,

requires the co-operation of the developer in terms of the delivery of design information and test results

Assurance components

EAL2 provides assurance by an analysis of the security functions using

a functional and interface specification, guidance documentation and the high-level design of the TOE,

to understand the security behaviour. a configuration list for the TOE, and evidence of secure delivery procedures.

The analysis is supported by independent testing of the TOE security functions, evidence of developer testing based on the functional specification, selective independent confirmation of the developer test results, strength of function analysis, and evidence of a developer search for obvious vulnerabilities

This EAL represents a meaningful increase in assurance from EAL1 by requiring developer testing, a vulnerability analysis, and independent testing based upon more detailed TOE specifications.

Objectives

permits a developer to gain maximum assurance from positive security engineering at the design stage without substantial alteration of existing sound development practices.

applicable in those circumstances where developers or users require a moderate level of independently assured security, and require a thorough investigation of the TOE and its development without substantial re-engineering.

Assurance components

EAL3 provides assurance by an analysis of the security functions, using

a functional and interface specification, guidance documentation, and the high-level design of the TOE,

to understand the security behaviour. the use of

development environment controls, TOE configuration management, and evidence of secure delivery procedures.

The analysis is supported by independent testing of the TOE security functions, evidence of developer testing based on the functional

specification and high-level design, selective independent confirmation of the developer test

results, strength of function analysis, and evidence of a developer search for obvious vulnerabilities.

This EAL represents a meaningful increase in assurance from EAL2 by requiring more complete testing coverage of the security functions and

mechanisms and/or procedures that provide some confidence that the TOE will not be tampered with during development.

Objectives

permits a developer to gain maximum assurance from positive security engineering based on good commercial development practices which, though rigorous, do not require substantial specialist knowledge, skills, and other resources.

applicable in those circumstances where developers or users require a moderate to high level of independently assured security in conventional commodity TOEs and are prepared to incur additional security-specific engineering costs.

Assurance components

EAL4 provides assurance by an analysis of the security functions, using

a functional and complete interface specification, guidance documentation, the high-level and low-level design of the TOE, a subset of the implementation,

to understand the security behaviour an informal model of the TOE security policy, the use of development environment controls , additional TOE configuration management including automation, and evidence of secure delivery procedures

The analysis is supported by independent testing of the TOE security functions, evidence of developer testing based on the functional specification and

high-level design, selective independent confirmation of the developer test results, strength of function analysis, evidence of a developer search for vulnerabilities, and an independent vulnerability analysis demonstrating resistance to

penetration attackers with a low attack potential.

This EAL represents a meaningful increase in assurance from EAL3 by requiring

more design description,

a subset of the implementation, and

improved mechanisms and/or procedures that provide confidence that the TOE will not be tampered with during development or delivery.

Objectives

permits a developer to gain maximum assurance from security engineering

Applicable where developers or users require a high level of independently assured security in a planned development and require a rigorous development approach without incurring unreasonable costs attributable to specialist security engineering techniques.

Assurance components

EAL5 provides assurance by

an analysis of the security functions, using

a functional and complete interface specification,

guidance documentation,

the high-level and low-level design of the TOE,

all of the implementation,

to understand the security behaviour.

a formal model of the TOE security policy,

a semiformal presentation of the functional specification and high-level design, and a semiformal demonstration of correspondence between them,

a modular TOE design,

the use of

a development environment controls,

comprehensive TOE configuration management including automation, and

evidence of secure delivery procedures.

The analysis is supported by independent testing of the TOE security functions, evidence of developer testing based on the functional specification, and high-level design

and low-level design, selective independent confirmation of the developer test results, strength of function analysis, evidence of a developer search for vulnerabilities, an independent vulnerability analysis demonstrating resistance to penetration attackers

with a moderate attack potential, and validation of the developer's covert channel analysis.

This EAL represents a meaningful increase in assurance from EAL4 by requiring semiformal design descriptions, the entire implementation, a more structured architecture, covert channel analysis, and improved mechanisms and/or procedures that provide confidence that the TOE will not be

tampered with during development.

Objectives

permits developers to gain high assurance from application of security engineering techniques to a rigorous development environment in order to produce a premium TOE for protecting high value assets against significant risks.

applicable to the development of security TOEs for application in high risk situations where the value of the protected assets justifies the additional costs.

Assurance components

EAL6 provides assurance by an analysis of the security functions, using

a functional and complete interface specification, guidance documentation, the high-level and low-level design of the of the TOE, a structured presentation of the implementation,

to understand the security behaviour, a formal model of the TOE security policy, a semiformal presentation of the functional specification, high-level design, and low-level design and a

semiformal demonstration of correspondence between them, a modular and layered TOE design, and the use of

a structured development process, development environment controls, comprehensive TOE configuration management including complete automation, and evidence of secure delivery procedures.

The analysis is supported by independent testing of the TOE security functions, evidence of developer testing based on the functional specification, high-level design and

low-level design, selective independent confirmation of the developer test results, strength of function analysis, evidence of a developer search for vulnerabilities, an independent vulnerability analysis demonstrating resistance to penetration attackers

with a high attack potential, and validation of the developer's systematic covert channel analysis.

This EAL represents a meaningful increase in assurance from EAL5 by requiring more comprehensive analysis, a structured representation of the implementation, more architectural structure (e.g. layering), more comprehensive independent vulnerability analysis, systematic covert channel identification, and improved configuration management and development environment controls.

Objectives

applicable to the development of security TOEs for application in extremely high risk situations and/or where the high value of the assets justifies the higher costs.

Assurance components

EAL7 provides assurance by an analysis of the security functions, using

a functional and complete interface specification, guidance documentation, the high-level and low-level design of the TOE, and a structured presentation of the implementation,

to understand the security behaviour. a formal model of the TOE security policy, a formal presentation of the functional specification and high-level design, a semiformal presentation of the low-level design, formal and semiformal demonstration of correspondence between them a modular, layered and simple TOE design , and the use of

a structured development process, development environment controls, comprehensive TOE configuration management including complete automation, and evidence of secure delivery procedures.

The analysis is supported by independent testing of the TOE security functions, evidence of developer testing based on the functional specification

high-level design, low-level design and implementation representation, complete independent confirmation of the developer test results, strength of function analysis, evidence of a developer search for vulnerabilities an independent vulnerability analysis demonstrating resistance to

penetration attackers with a high attack potential , and validation of the developer‘s systematic covert channel analysis.

This EAL represents a meaningful increase in assurance from EAL6 by requiring more comprehensive analysis using formal representations and formal

correspondence, and comprehensive testing.

Information Technology — SecurityTechniques — Evaluation Criteria For ITSecurity Part3:Security Assurance Requirements (ISO/IEC15408-3)