(My) CSSLP Notes – Secure Software Concepts

Note: This notes were strongly inspired by the following book: CSSLP Certification All in one.

General Security Concepts

BasicsCSSLP-logo

The security of IT systems can be defined using the following attributes:

  • confidentiality – how the system prevents the disclosure of information.
  • integrity – how the system protects data from the unauthorized access.
  • availability – access to the system by authorized personnel.
  • authentication – process of determining the identity of a user. Three methods can be used to authenticate a user:
    • something you know (ex: password, pin code)
    • something you have (ex: token, card)
    • something you are (ex: biometrics mechanisms)
  • authorization – process of applying access control rules to a user process to determine if a particular user process can access an object.
  • accounting (auditing) – records historical events on a system.
  • non-repudiation – preventing a subject from denying a previous action with an object in a system.

System principles

  • session management – design and implementation of controls to ensure that the communications channels are secured from unauthorized access and disruption of communications.
  • exception management – the process of handling any errors that could appear during the system execution.
  • configuration management – identification and management of the configuration items (initialization parameters, connection strings, paths, keys).

Secure design principles

  • good enough security – there is a trade off between security and other aspects associated with a system. The level of required security must be determined at design time.
  • least privilege – a subject should have only the necessary rights and privileges to perform a specific task.
  • separation of duties – for any given task, more than one individual needs to be involved.
  • defense in depth (layered security) – apply multiple dissimilar security defenses.
  • fail-safe – when a system experience a failure, it should fail to a safe state; all the attributes associated with the system security (confidentiality, integrity, availability) should be appropriately maintained.
  • economy of mechanism – keep the design of the system simple and less complex; reduce the number of dependencies and/or services that the system needs in order to operate.
  • complete mediation – checking permission each time subject requests access to objects.
  • open design – design is not a secret, implementation of safeguard is. (ex: cryptography algorithms are open but the keys used are secret)
  • least common mechanism – minimize the amount of mechanism common to more than one user and depended on by all users. Every shared mechanism (especially one involving shared variables) represents a potential information path between users and must be designed with great care to be sure it does not unintentionally compromise security.
  • psychological acceptability – accessibility to resources should not be inhibited by security mechanisms. If security mechanisms hinder the usability or accessibility of resources, then users may opt to turn off those mechanisms.
  • weakest link – attackers are more likely to attack a weak spot in a software system than to penetrate a heavily fortified component.
  • leverage existing components – component reuse have many advantages, including the increasing of efficiency and security. From the security point of view the component reuse is reducing the attack surface.
  • single point of failure – a system design should not be susceptible to a single point of failure.

Security Models

Access Control Models

Access controls define what actions a subject can perform on specific objects.

  • Bell-LaPadula confidentiality model – It is focused on maintaining the confidentiality of objects. Bell-LaPadula operates by observing two rules: the Simple Security Property and the * Security Property.
    • The Simple security property states that there is “no read up:” a subject at a specific classification level cannot read an object at a higher classification level.
    • The * Security Property is “no write down:”a subject at a higher classification level cannot write to a lower classification level.
  • Take-Grant  – systems specify the rights that a subject can transfer to a from another subject or object. The model is based on representation of the controls in forms of directed graphs with the vertices being the subjects and the objects. The edges between them represent the right between the subject and objects. The representation of rights takes the form of {t (take), g (grant), r (read), w (write)}.
  • Role-based Access control – users are assign a set of roles they may perform. The roles are associated to the access permissions necessary to perform the tasks.
  • MAC (Mandatory Access Control) Model – in MAC systems the owner or subject cannot determine whether access is to be granted to another subject; it is the job of the operating system to decide.
  • DAC (Discretionary Access Control) Model – in DAC systems the owner of an object can decide which other subjects may have access to the object what specific access they may have.

Integrity Models

  • Biba integrity model  – (sometimes referred as Bell-LaPadula upside down) was the first formal integrity model.  Biba is the model of choice when integrity protection is vital. The Biba model has two primary rules: the Simple Integrity Axiom and the * Integrity Axiom. 
    • The Simple Integrity Axiom is “no read down:”a subject at a specific classification level cannot read data at a lower classification. This protects integrity by preventing bad information from moving up from lower integrity levels.
    • The * Integrity Axiom is “no write up:”a subject at a specific classification level cannot write to data at a higher classification. This protects integrity by preventing bad information from moving up to higher integrity levels.
  • Clark-Wilson  –  (this is an informal model) that protects integrity by requiring subjects to access objects via programs. Because the programs have specific limitations to what they can and cannot do to objects, Clark-Wilson effectively limits the capabilities of the subject.Clark-Wilson uses two primary concepts to ensure that security policy is enforced; well-formed transactions and Separation of Duties.

Information Flow Models

Information in a system must be protected when at rest, in transit and in use.

  • The Chinese Wall model – designed to avoid conflicts of interest by prohibiting one person, such as a consultant, from accessing multiple conflict of interest categories (CoIs). The Chinese Wall model requires that CoIs be identified so that once a consultant gains access to one CoI, they cannot read or write to an opposing CoI.

 

Risk Management

Vocabulary

  • risk – possibility of suffering harm or loss
  • residual risk – risk that remains after a control was added to mitigate the initial risk.
  • total risk – the sum of all risks associated with an asset.
  • asset – resource an organization needs to conduct his business.
  • threat – circumstance or event with the potential to cause harm to an asset.
  • vulnerability – any characteristic if an asset that can be exploited by a threat to cause harm.
  • attack – attempting to use a vulnerability.
  • impact – loss resulting when a threat exploits a vulnerability.
  • mitigate – action taken to reduce the likelihood of a threat.
  • control – measure taken to detect, prevent or mitigate the risk associated with a threat.
  • risk assessment – process of identifying risks and mitigating actions.
  • qualitative risk assessment – subjectively determining the impact of an event that effects assets.
  • quantitative risk assessment –  objectively determining the impact of an event that effects assets.
  • single loss expectation (SLE) – linked to the quantitative risk assessment, it represents the monetary loss or impact of each occurrence of a threat.
    • SLE = asset value * exposure factor
  • exposure factor – linked to the quantitative risk assessment, is a measure of the magnitude of a loss.
  • annualized rate of occurrence (ARO) – linked to the quantitative risk assessment, is the frequency with an event is expected to occur on an annualized basis.
    • ARO = number of events / number of years
  • annualized loss of expectancy (ALE) – linked to the quantitative risk assessment, it represents how much an event is expected to cost per year.
    • ALE = SLE * ARO

Types of risks:

  • Business Risks:
    • fraud
    • regulatory
    • treasury management
    • revenue management
    • contract management
  • Technology Risks:
    • security
    • privacy
    • change management

Types of controls

Controls can be classified on types of actions they perform. Three classes of controls exist:

  • administrative
  • technical
  • physical

For each of these classes, there are four types of controls:

  • preventive (deterrent) – used to prevent the vulnerability
  • detective – used to detect the presence of an attack.
  • corrective (recovery) – correct a system after a vulnerability is exploited and an impact has occurred; backups are  a common form of corrective controls.
  • compensation – designed to act when a primary set of controls has failed.

Risk management models

General risk management model

The steps contained in a general risk management model:

  1. Asset identification – identify and clarify all the assets, systems and processes that need to be protected.
  2. Threat assessment – identify the threats and vulnerabilities associated with each asset.
  3. Impact determination and qualification
  4. Control design and evaluation – determine which controls to put in place to mitigate the risks.
  5. Residual risk management – evaluate residual risks to identify where additional controls are needed.

Risk management model proposed by Software Engineering Institute

SEI model steps :

  1. Identity – enumerate potential risks.
  2. Analyze – convert the risk data gather into information that can be used to make decisions.
  3. Plan – decide the actions to take to mitigate them.
  4. Track – monitor the risks and mitigations plans.
  5. Control – make corrections for deviations from the risk mitigation plan.

Security Policies and Regulations

One of the most difficult aspects of prosecution of computer crimes is attribution. Meeting the burden of proof requirement in criminal proceedings, beyond a reasonable doubt, can be difficult given an attacker can often spoof the source of the crime or can leverage different systems under someone else’s control.

Intellectual property

Intellectual property is protected by the U.S law under one of four classifications:

  • patents – Patents provide a monopoly to the patent holder on the right to use, make, or sell an invention for a period of time in exchange for the patent holder’s making the invention public.
  • trademarks – Trademarks are associated with marketing: the purpose is to allow for the creation of a brand that distinguishes the source of products or services.
  • copyrights – represents a type of intellectual property that protects the form of expression in artistic, musical, or literary works, and is typically denoted by the circle c symbol. Software is typically covered by copyright as if it were a literary work. Two important limitations on the exclusivity of the copyright holder’s monopoly exist: the doctrines of first sale and fair use. The first sale doctrine allows a legitimate purchaser of copyrighted material to sell it to another person. If the purchasers of a CD later decide that they no longer cared to own the CD, the first sale doctrine gives them the legal right to sell the copyrighted material even though they are not the copyright holders.
  • trade secrets – business-proprietary information that is important to an organization’s ability to compete. Software source code or firmware code are examples of computer-related objects that an organization may protect as trade secrets.

Privacy and data protection laws

Privacy and data protection laws are enacted to protect information collected and maintained on individuals from unauthorized disclosure or misuse.

Several important pieces of privacy and data protection legislation include :

  • U.S. Federal Privacy Act of 1974 – protects records and information maintained by U.S. government agencies about U.S. citizens and lawful permanent residents.
  •  U.S. Health Insurance Portability and Accountability Act (HIPAA) of 1996 – seeks to guard protected health information from unauthorized use or disclosure.
  • Payment Card Industry Data Security Standard (PCI-DSS) – the goal is to ensure better protection of card holder data through mandating security policy, security devices, control techniques and monitoring of systems and networks.
  • U.S. Gramm-Lech-Bliley Financial Services Modernization Act (GLBA) – requires financial institutions to protect the confidentiality and integrity of consumer financial information.
  • U.S. Sarbanes-Oxley Act of 2002 (SOX) – the primary goal of SOX is to ensure adequate financial disclosure and financial auditor independence.

Secure Software Architecture – Security Frameworks

  • COBIT (Control Objectives for Information and Related Technology)– assist management in bringing the gap between control requirements, technological issues and business risks.
  • COSO (Committee of Sponsoring Organizations of the Treadway Commission) – COSO has established a Enterprise Risk Management -Integrated Framework against which companies and organizations may assess their control systems.
  • ITIL (Information Technology Infrastructure Library) – describes a set of practices focusing on aligning IT services with business needs.
  • SABSA (Sherwood Applied Business Security Architecture) – framework and methodology for developing risk-driven enterprise information security architecture.
  • CMMI (Capability Maturity Model Integration) – process metric model that rates the process maturity of an organization on a 1 to 5 scale.
  • OCTAVE (Operationally Critical Threat, Asset and Vulnerability Evaluation) – suite of tools, techniques and methods for risk-based information security assessment.

 

Software Development Methodologies

Secure Development Lifecycle Components

  • software team awareness and education – all team members should have appropriate training. The key element of team awareness and education is to ensure that all the members are properly equipped with the correct knowledge.
  • gates and security requirements – the term gates it signifies a condition that one must pass through. To pass the security gate a review of the appropriate security requirements is conducted.
  • threat modeling – design technique used to communicate information associated with a threat throughout the development team (for more infos’ you could check my other ticket : threat modeling for mere mortals).
  • fuzzing – a test technique where the tester applies a series of inputs to an interface in an automated fashion and examines the output for undesired behaviors.
  • security reviews – process to ensure that the security-related steps are being carried out and not being short-circuited.

Software Development Models

  • waterfall model – is a linear application development model that uses rigid phases; when one phase ends, the next begins.
  • spiral model – repeats steps of a project, starting with modest goals, and expanding outwards in ever wider spirals (called rounds). Each round of the spiral constitutes a project, and each round may follow traditional software development methodology such as Modified Waterfall. A risk analysis is performed each round.
  • prototype model – working model of software with some limited functionality. Prototyping is used to allow the users evaluate developer proposals and try them out before implementation.
  • agile model
    • Scrum  – contain small teams of developers, called the Scrum Team. They are supported by a Scrum Master, a senior member of the organization who acts like a coach for the team. Finally, the Product Owner is the voice of the business unit.
    • Extreme Programming (XP) – method that uses pairs of programmers who work off a detailed specification.

Microsoft Security Development Lifecycle

SDL is software development process designed ti enable development teams to build more secure software and address security compliance requirements.

SDC is build around the following three elements:

  • (security) by design – the security thinking is incorporated as part of design process.
  • (security) by default – the default configuration of the software is by design as secure as possible.
  • (security) in deployment – security and privacy elements are properly understood and managed through the deployment process.

SDL components:

  • training   security training for all personnel, targeted to their responsibility associated with the development effort.
  • requirements
    • establishment of the security and privacy requirements for the software.
    • creation of quality gates ans bug bars. Defining minimum acceptable levels of security and privacy quality at the start helps a team understand risks associated with security issues, identify and fix security bugs during development, and apply the standards throughout the entire project.Setting a meaningful bug bar involves clearly defining the severity thresholds of security vulnerabilities (for example, no known vulnerabilities in the application with a “critical” or “important” rating at time of release) and never relaxing it once it’s been set.
    • development of security and privacy risk assessment. Examining software design based on costs and regulatory requirements helps a team identify which portions of a project will require threat modeling and security design reviews before release and determine the Privacy Impact Rating of a feature, product, or service.
  • design – establish design requirements, perform attack/surface analysis/reduction and use threat modeling.
  • implementation – application of secure coding practices and the use of static program checkers to find common errors.
  • verification – perform dynamic analysis (tools that monitor application behavior for memory corruption, user privilege issues, and other critical security problems), fuzz testing and conduct attack surface review.
  • release – conduct final security review and create an incident response plan.
  • response – execute incident response plan.

Book review: Software Security: Building Security in – Part II: Seven Touchpoints for Software Security

This is a review of the second part of the Software Security: Building Security in book.

Chapter 3: Introduction to Software Security TouchpointsSecuritySoftwareBookCover

This is an introductory chapter for the second part of the book. A very brief description is made for every security touch point.

Each one of the touchpoints are applied on a specific artifact and each touchpoints represents either a destructive or constructive activity. Based on the author experience, the ideal order based on effectiveness in which the touch points should be implemented is the following one:

  1. Code Review (Tools). Artifact: code. Constructive activity.
  2. Architectural Risk Analysis. Artifact: design and specification. Constructive activity.
  3. Penetration Testing. Artifact: system in its environment. Destructive activity
  4. Risk-Based Security Testing. Artifact system. Mix between destructive and constructive activities
  5. Abuse Cases. Artifact: requirements and use cases. Predominant destructive activity.
  6. Security Requirements. Artifact: requirements. Constructive activity.
  7. Security Operations. Artifact: fielded system. Constructive activity.

Another idea to mention that is worth mentioning is that the author propose to add the securty aspects as soon as possible in the software development cycle;moving left as much as possible (see the next figure that pictures the applicability of the touchpoints in the development cycle); for example it’s much better to integrate security in the requirements or architecture and design (using the risk analysis and abuse cases touchpoints) rather than waiting for the penetration testing to find the problems.

Security touchpoints

Security touchpoints

Chapter 4: Code review with a tool

For the author the code review is essential in finding security problems early in the process. The tools (the static analysis tools) can help the user to make a better job, but the user should also try to understand the output from the tool; it’s very important to not just expect that the tool will find all the security problems with no further analysis.

In the chapter a few tools (commercial or not) are named, like CQual, xg++, BOON, RATS, Fortify (which have his own paragraph) but the most important part is the list of key characteristics that a good analysis tool should have and some of the characteristics to avoid.

The key characteristics of a static analysis tool:

  • be designed for security
  • support multi tiers architecture
  • be extensible
  • be useful for security analysts and developers
  • support existing development processes

The key characteristics of a static analysis tool to avoid:

  • too many false positives
  • spotty integration with the IDE
  • single-minded support for C language

Chapter 5: Architectural Risk Analysis

Around 50% of the security problems are the result of design flows, so performing an architecture risk analysis at design level is an important part of a solid software security program.

In the beginning of the chapter the author present very briefly some existing security risk analysis methodologies: STRIDE (Microsoft), OCTAVE (Operational Critical Threat, Asset and Vulnerability Evaluation), COBIT (Control Objectives for Information and Related Technologies).

Two things are very important for the author; the ara (architectural risk analysis) must be integrated in and with the Risk Management Framework (presented briefly in Book review: Software Security: Building Security in – Part I: Software Security Fundamentals), and we must have a “forest-level” view of the system.

In the last part of the chapter the author present the Cigital way of making architectural risk analysis. The process has 3 steps:

  1. attack resistance analysis – have as goal to define how the system should behave against known attacks.
  2. ambiguity analysis – have as goal to discover new types of attacks or risks, so it relies heavily on the experience of the persons performing the analysis.
  3. weakness analysis – have as goal to understand end asses the impact of external software dependencies.
Process diagram for architectural risk analysis

Process diagram for architectural risk analysis

Chapter 6: Software Penetration Testing

The chapter starts by presenting how the penetration testing is done today. For the author, the penetration tests are misused and are used as a “feel-good exercise in pretend security”. The main problem is that the penetration tests results cannot guarantee that the system is secured after all the found vulnerabilities had been fixed and the findings are treated as a final list of issues to be fixed.

So, for the author the penetration tests are best suited to probing (live like) configuration problems and other environmental factors that deeply impact software security. Another idea is to use the architectural risk analysis as a driver for  the penetration tests (the risk analysis could point to more weak part(s) of the system, or can give some attack angles). Another idea, is to treat the findings as a representative sample of faults in the system and all the findings should be incorporated back into the development cycle.

Chapter 7: Risk-Based Security Testing

Security testing should start as the feature or component/unit level and (as the penetration testing) should use the items from the architectural risk analysis to identify risks. Also the security testing should continue at system level and should be directed at properties of the integrated software system. Basically all the tests types that exist today (unit tests, integration tests) should also have a security component and a security mindset applied.

The security testing should involve two approaches:

  • functional security testing: testing security mechanism to ensure that their functionality is properly implemented (kind of white hat philosophy).
  • adversarial security testing: tests that are simulating the attacker’s approach (kind of black hat philosophy).

For the author the penetration tests represents a outside->in type of approach, the security testing represents an inside->out approach focusing on the software products “guts”.

Chapter 8: Abuse Case Development

The abuse case development is done in the requirements phase and it is intimately linked to the requirements and use cases. The basic idea is that as we define requirements that suppose to express how the system should behave under a correct usage, we should also define how the system should behave if it’s abused.

This is the process that is proposed by the author to build abuse cases.

Diagram for building abuse cases

Diagram for building abuse cases

The abuse cases are creating using two sources, the anti-requirements (things that you don’t want your software to do) and attack models, which are known attacks or attack types that can apply to your system. Once they are done, the abuse cases can be used as entry point for security testing and especially for the architectural risk analysis.

Chapter 9: Software Security Meets Security Operations

The main idea is that the security operations peoples and software developers should work together and each category can (and should) learn from the other (category).

The security operation peoples have the security mindset and can use this mindset and their experience in some of the touchpoints presented previously; mainly abuse cased, security testing, architectural risk analysis and penetration testing.

Book review: Software Security: Building Security in – Part I: Software Security Fundamentals

This is a review of the first part of the Software Security: Building Security in book.

Chapter 1: Defining a disciplineSecuritySoftwareBookCover

This chapter lands out the landscape for the entire book; the author presents his view on the today challenges in having secure holes free software.
In the today world, the software is everywhere, from microwaves oven to nuclear power-stations, so the “old view” of seeing the software applications as “black boxes” than can be protected using firewalls and IDS/IPS it’s not valid anymore.

And just to make the problem even harder, the computing systems and the software applications are more and more interconnected must be extensible and have more and more complex features.

The author propose a taxonomy of the security problems that can be affected the software applications:

  • defect: a defect is a problem that may lie dormant in software only to surface in a fielded system with major consequences.
  • bug: an implementation-level software problem; only fairy simple implementations errors. A large panel of tools are capable to detect a range of implementation bugs.
  • flaw: a problem at a deeper level; a flow is something that can be present at the code level but it can be also present or absent at the design level. What is very important to remark is that the automated technologies to detect design-level flows do not yet exist, through manual risk-analysis can identity flows.
  • risk: flaws and bugs lead to risk. Risk capture the chance that a flaw or a bug will impact the purpose of a software.

In order to solve the problem of the software security, the author propose a cultural shift based on three pillars: applied risk management, software security touchpoints and knowledge.

Pillar 1 Applied Risk Management

For the author under the risk management names there 2 different parts; the application of risk analysis at the architectural level (also known as threat modeling or security design analysis or architectural risk analysis) and tracking and mitigating risks as a full life-cycle activity (the author call this approach, the risk management framework – RMF).

Pillar 2 Software security Touchpoints.

Touchpoint it’s just a fancy word for “best practices”. Today there are best practices for design and coding of software system and as the security became a property of a software system, then best practices should also be used to tackle the security problems.Here are the (seven) touch points and where exactly are applied in the development process.

Security Touchpoints

Security Touchpoints

The idea is to introduce as deeply as possible the touch points in the development process. The part 2 of the book is dedicated to the touchpoints.

Pillar 3 Knowledge

For the author the knowledge management and training should play a central role in encapsulation and sharing the security knowledge.The software security knowledge can be organized into seven knowledge catalogs:

  • principles
  • guideline
  • rules
  • vulnerabilities
  • exploits
  • attack patterns
  • historical risks

How to build the security knowledge is treated in the part 3 of the book.

Chapter 2: A risk management framework

This chapter presents in more details a framework to mitigate the risks as a full lifecycle activity; the author calls this framework the RMF (risk Management Framework).

The purpose of the RMF is to allow a consistent and repeatable expert-driven approach to risk management but the main goal is to find, rank, track and understand the software security risks and how these security risks can affect the critical business decisions.

Risk Management Analysis steps

Risk Management Analysis steps

The RMF consists of five steps:

  1. understand the business context The goal of this step is describe the business goals in order to understand the     types of software risks to care about.
  2. identify the business and technical risks. Business risk identification helps to define and steer the use of particular technological methods for measuring and mitigating software risk.The technical risks should be identified and mapped (through business risk) to business goals.
  3. synthesize and rank the risks. The ranking of the risks should take in account which business goals are the most important, which business goals are immediately threatened and how the technical risks will impact the business.
  4. define a risk mitigation strategy. Once the risks have been identified, the mitigation strategy should take into account cost, implementation time, likelihood of success and the impact
  5. carry out required fixes and validate that they are correct. This step represents the execution of the risk mitigation strategy; some metrics should be defined to measure the progress against risks, open risks remaining.

Even if the framework steps are presented sequentially, in practice the steps can overlap and can occur in parallel with standards software development activities. Actually the RMF can be applied at several different level; project level, software lifecycle phase level, requirement analysis, use case analysis level.

(My) CISSP Notes – Information Security Governance and Risk Management

Note: This notes were made using the following books: “CISPP Study Guide” and “CISSP for dummies”.
The Information Security Governance and Risk Management domain focuses on risk analysis and mitigation. This domain also details security governance, or the organizational structure required for a successful information security program.

CIA triad

  •  Confidentiality seeks to prevent the unauthorized disclosure of information. In other words, confidentiality seeks to prevent unauthorized read access to data.
  • Integrity seeks to prevent unauthorized modification of information. In other words, integrity seeks to prevent unauthorized write.
  • Availability ensures that information is available when needed.

The CIA triad may also be described by its opposite: Disclosure, Alteration, and Destruction (DAD).

The term “AAA” is often used, describing cornerstone concepts Authentication, Authorization, and Accountability.

  • Authorization describes the actions you can perform on a system once you have identified and authenticated.
  • Accountability holds users accountable for their actions. This is typically done by logging and analyzing audit data
  • Nonrepudiation means a user cannot deny (repudiate) having performed a transaction. It combines authentication and integrity: nonrepudiation authenticates the identity of a user who performs a transaction, and ensures the integrity of that transaction. You must have both authentication and integrity to have nonrepudiation.

Least privilege means users should be granted the minimum amount of access (authorization) required to do their jobs, but no more.

Need to know is more granular than least privilege: the user must need to know that specific piece of information before accessing it.

Defense-in-Depth (also called layered defenses) applies multiple safeguards (also called controls: measures taken to reduce risk) to protect an asset.

Risk analysis

  • Assets are valuable resources you are trying to protect.
  • A threat is a potentially harmful occurrence, like an earthquake, a power outage, or a network-based worm. A threat is a negative action that may harm a system.
  • A vulnerability is a weakness that allows a threat to cause harm.

Risk = Threat × Vulnerability

To have risk, a threat must connect to a vulnerability.

The “Risk = Threat × Vulnerability” equation sometimes uses an added variable called impact: “Risk = Threat × Vulnerability × Impact.

Impact is the severity of the damage, sometimes expressed in dollars.

Loss of human life has near-infinite impact on the exam. When calculating risk using the “Risk = Threat × Vulnerability × Impact” formula, any risk involving loss of human life is extremely high, and must be mitigated.

The Annualized Loss Expectancy (ALE) calculation allows you to determine the annual cost of a loss due to a risk. Once calculated, ALE allows you to make informed decisions to mitigate the risk.

The Asset value (AV) is the value of the asset you are trying to protect.

PIIPersonally Identifiable Information

The Exposure Factor (EF) is the percentage of value an asset lost due to an incident.

The Single Loss Expectancy (SLE) is the cost of a single loss. SLE  = AV x EF.

The Annual Rate of Occurrence (ARO) is the number of losses you suffer per year.

The Annualized Loss Expectancy (ALE) is your yearly cost due to a risk. It is calculated by multiplying the Single Loss Expectancy (SLE) times the Annual Rate of Occurrence (ARO).

The Total Cost of Ownership (TCO) is the total cost of a mitigating safeguard. TCO combines upfront costs (often a one-time capital expense) plus annual cost of maintenance, including staff hours, vendor maintenance fees, software subscriptions, etc.

The Return on Investment (ROI) is the amount of money saved by implementing a safeguard.

Risk Choices

Once we have assessed risk, we must decide what to do. Options include accepting the risk, mitigating or eliminating the risk, transferring the risk, and avoiding the risk.

Quantitative and Qualitative Risk Analysis are two methods for analyzing risk. Quantitative Risk Analysis uses hard metrics, such as dollars. Qualitative Risk Analysis uses simple approximate values. Quantitative is more objective; qualitative is more subjective.

The risk management process

Risk Management Guide for Information Technology Systems (see http://csrc.nist.gov/publications/nistpubs/800-30/sp800-30.pdf).

The guide describes a 9-step Risk Analysis process:

1. System Characterization – System characterization describes the scope of the risk management effort and the systems that will be analyzed.

2. Threat Identification –

Threat Identification and Vulnerability Identification, identify the threats and vulnerabilities, required to identify risks using the “Risk = Threat × Vulnerability” formula.

3. Vulnerability Identification

4. Control Analysis – Control Analysis, analyzes the security controls (safeguards) that are in place or planned to mitigate risk.

5. Likelihood Determination

6. Impact Analysis

7. Risk Determination

8. Control Recommendations

9. Results Documentation

Information Security Governance

Information Security Governance is information security at the organizational level.

Security Policy and related documents

  • Policies are high-level management directives. Policy is high level: it does not delve into specifics. All policy should contain these basic components: Purpose, Scope, Responsibilities , Compliance.  NIST Special Publication 800-12 (see http://csrc.nist.gov/publications/nistpubs/800-12/800-12-html/chapter5.html) discusses three specific policy types: program policy, issue-specific policy, and system-specific policy. Program policy establishes an organization’s information security program.
  • A procedure is a step-by-step guide for accomplishing a task. They are low level and specific. Like policies, procedures are mandatory.
  • A standard describes the specific use of technology, often applied to hardware and software. Standards are mandatory. They lower the Total Cost of Ownership of a safeguard. Standards also support disaster recovery.
  • Guidelines are recommendations (which are discretionary).
  • Baselines are uniform ways of implementing a safeguard.

Roles and responsibilities

Primary information security roles include senior management, data owner, custodian, and user.

  • Senior Managementcreates the information security program and ensures that is properly staffed, funded, and has organizational priority. It is responsible for ensuring that all organizational assets are protected.
  • The Data Owner (also called information owner or business owner) is a management employee responsible for ensuring that specific data is protected. Data owners determine data sensitivity labels and the frequency of data backup. The Data Owner (capital “O”) is responsible for ensuring that data is protected. A user who “owns” data (lower case “o”) has read/write access to objects.
  • A Custodian provides hands-on protection of assets such as data. They perform data backups and restoration, patch systems, configure antivirus software, etc. The Custodians follow detailed orders; they do not make critical decisions on how data is protected.
  • Users must follow the rules: they must comply with mandatory policies procedures, standards, etc.

Complying with laws and regulations is a top information security management priority: both in the real world and on the exam.

The exam will hold you to a very high standard in regard to compliance with laws and regulations. We are not expected to know the law as well as a lawyer, but we are expected to know when to call a lawyer.

The most legally correct answer is often the best for the exam.

Privacy is the protection of the confidentiality of personal information.

Due care and Due Diligence

Due care is doing what a reasonable person would do. It is sometimes called the “prudent man” rule. The term derives from “duty of care”: parents have a duty to care for their children, for example. Due diligence is the management of due care.

Due care is informal; due diligence follows a process.

Gross negligence is the opposite of due care. It is a legally important concept. If you suffer loss of PII, but can demonstrate due care in protecting the PII, you are on legally stronger ground, for example.

Auditing and Control Frameworks

Auditing means verifying compliance to a security control framework (or published specification).

A number of control frameworks are available to assist auditing Risk Analysis. Some, such as PCI (Payment Card Industry), are industry-specific (vendors who use credit cards in the example). Others, such as OCTAVE, ISO 17799/27002, and COBIT.

OCTAVE stands for Operationally Critical Threat, Asset, and Vulnerability Evaluation, a risk management framework from Carnegie Mellon University. OCTAVE describes a three-phase process for managing risk. Phase 1 identifies staff knowledge, assets, and threats. Phase 2 identifies vulnerabilities and evaluates safeguards. Phase 3 conducts the Risk Analysis and develops the risk mitigation strategy. OCTAVE is a high-quality free resource which may be downloaded from: http://www.cert.org/octave/ ISO 17799 and the ISO 27000 Series.

ISO 17799 had 11 areas, focusing on specific information security controls:

1. Policy

2. Organization of information security

3. Asset management

4. Human resources security

5. Physical and environmental security

6. Communications and operations management

7. Access control

8. Information systems acquisition, development, and maintenance

9. Information security incident management

10. Business continuity management

11. Compliance3 ISO 17799 was renumbered to ISO 27002 in 2005, to make it consistent with the 27000 series of ISO security standards.

Simply put, ISO 27002 describes information security best practices (Techniques), and ISO 27001 describes a process for auditing (requirements) those best practices.

COBIT (Control Objectives for Information and related Technology) is a control framework for employing information security governance best practices within an organization.  COBIT was developed by ISACA (Information Systems Audit and Control Association.

ITIL(Information Technology Infrastructure Library) is a framework for providing best services in IT Service Management (ITSM). ITIL contains five “Service Management Practices—Core Guidance” publications: • Service Strategy • Service Design • Service Transition • Service Operation • Continual Service Improvement

Certification and Accreditation

Certification is a detailed inspection that verifies whether a system meets the documented security requirements.

Accreditation is the Data Owner’s acceptance of the risk represented by that system.