Jan 18, 2012

Learn Ethical Hacking Basics Session II

Goals of Security


Understand the security triangle, also known as CIA (confidentiality, integrity, and availability). 

There are many ways in which security can be achieved, but it’s universally agreed that the security triad of confidentiality, integrity, and availability (CIA) form the basic building blocks of any good security initiative. 

Confidentiality addresses the secrecy and privacy of information. Physical examples of confidentiality include locked doors, armed guards, and fences. Logical examples of confidentiality can be seen in passwords, encryption, and firewalls. In the logical world, confidentiality must protect data in storage and in transit. For a real-life example of the failure of confidentiality, look no further than the recent news reports that have exposed how several large-scale breaches in confidentiality were the result of corporations, such as Time Warner and City National Bank, misplacing or losing backup tapes with customer accounts, names, and credit information. The simple act of encrypting thebackup tapes could have prevented or mitigated the damage. 

Integrity is the second piece of the CIA security triad. Integrity provides for the correctness of information. It allows users of information to have confidence in its correctness. Correctness doesn’t mean that the data is accurate, just that it hasn’t been modified in storage or transit. Integrity can apply to paper or electronic documents. It is much easier to verify the integrity of a paper document than an electronic one. Integrity in electronic documents and data is much more difficult to protect than in paper ones. Integrity must be protected in two modes: storage and transit. 

Information in storage can be protected if you use access and audit controls. Cryptography can also protect information in storage through the use of hashing algorithms. Real-life examples of this technology can be seen in programs such as Tripwire, MD5Sum, and Windows File Protection (WFP). Integrity in transit can be ensured primarily by the protocols used to transport the data. These security controls include hashing and cryptography. 

Availability is the third leg of the CIA triad. Availability simply means that when a legitimate user needs the information, it should be available. As an example, access to a backup facility 24x7 does not help if there are no updated backups from which to restore. Backups are one of the ways that availability is ensured. Backups provide a copy of critical information should files and data be destroyed or equipment fail. Failover equipment is another way to ensure availability. Systems such as redundant array of inexpensive disks (RAID) and subscription services such as redundant sites (hot, cold, and warm) are two other examples. Disaster recovery is tied closely to availability, as it’s all about getting critical systems up and running quickly. Denial of service (DoS) is an attack against availability. Although these attacks might not give access to the attacker, they dodeny legitimate users the access they require.


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