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This chapter is from the book

This chapter is from the book

Basic Security Principles

Confidentiality, integrity, and availability (CIA) define the basic building blocks of any good security program when defining the goals for network, asset, information, and/or information system security and are commonly referred to collectively as the CIA triad. Although the abbreviation CIA might not be as intriguing as the United States government’s spy organization, it is a concept that security professionals must know and understand.

Confidentiality addresses the secrecy and privacy of information and preventing unauthorized persons from viewing sensitive information. There are a number of controls used in the real world to protect the confidentiality of information, such as locked doors, armed guards, and fences. Administrative controls that can enhance confidentiality include the use of information classification systems, such as requiring sensitive data be encrypted. For example, news reports have detailed several large-scale breaches in confidentiality as a result of corporations misplacing or losing laptops, data, and even backup media containing customer account, name, and credit information. The simple act of encrypting this data could have prevented or mitigated the damage. Sending information in an encrypted format denies attackers the opportunity to intercept and sniff clear text information.

Integrity is the second leg in the security triad. Integrity provides accuracy of information, and offers users a higher degree of confidence that the information they are viewing has not been tampered with. Integrity must be protected while in storage, at rest, and in transit. Information in storage can be protected by using access controls and audit controls. Cryptography can enhance this protection through the use of hashing algorithms. Real-life examples of this technology can be seen in programs such as Tripwire, and MD5Sum. Likewise, integrity in transit can be ensured primarily by the use of transport protocols, such as PKI, hashing, and digital signatures.

The concept of availability requires that information and systems be available when needed. Although many people think of availability only in electronic terms, availability also applies to physical access. If, at 2 a.m., you need access to backup media stored in a facility that allows access only from 8 a.m. to 5 p.m., you definitely have an availability problem. Availability in the world of electronics can manifest itself in many ways. Access to a backup facility 24 × 7 does little good if there are no updated backups to restore from.

Backups are the simplest way to ensure availability. Backups provide a copy of critical information, should data be destroyed or equipment fail. Failover equipment is another way to ensure availability. Systems such as redundant arrays of independent disks (RAID) and redundant sites (hot, cold, and warm) are two other examples. Disaster recovery is tied closely to availability because it’s all about getting critical systems up and running quickly.

Which link in the security triad is considered most important? That depends. In different organizations with different priorities, one link might take the lead over the other two. For example, your local bank might consider integrity the most important; however, an organization responsible for data processing might see availability as the primary concern, whereas an organization such as the NSA might value confidentiality the most. Finally, you should be comfortable seeing the triad in any form. Even though this book refers to it as CIA, others might refer to it as AIC, or as CAIN (where the “N” stands for nonrepudiation).

Security management does not stop at CIA. These are but three of the core techniques that apply to asset security. True security requires defense-in-depth. In reality, many techniques are required to protect the assets of an organization; take a moment to look over Figure 2.1.

Figure 2.1

Figure 2.1 Asset protection triad.

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