As the name implies, this ebook is about securing your home or your business computer.  In the last few years, the use of computers in the home and in business has increased considerably.   During this period, large computer networks have been built to connect these computer systems. Computers connected to these networks are often operated and owned by different organizations, each with their own views of security. In such a scenario, it is difficult to define a secure system that fits the viewpoint of each organization.

When some people think of computer security, they think of their credit card numbers, social security numbers, and other personal information. Knowing how to protect private information from those who would exploit it is very important, however, that is only one part of computer security.  And computer security means protecting yourself from involvement in costly and possibly illegal activity on the Internet.  Furthermore, there are also many hoaxes and jokes circulated on the Internet that must be dealt with.

Computer security also mean protecting files from viruses, be they malicious or not, and protecting data from fallible hardware and crashing computers.  Computer security means protecting yourself and/or your organization from involvement in costly and possibly illegal activity on the Internet.  This may require putting administrative and personnel computer security policies in force in the workplace.   

This book, while covering major security how-to's, will also serve as a guide to the sea of information known as the Internet pointing you, the reader, in the right direction to background information enabling you to successfully navigate the world of computer security.  This book will also serve as a reference book, and Chapter 22, Computer Security Resources on the Web provides you with a list of useful websites containing further instruction and a list of articles.

 

Types of Computer Security

Hardware Security

Hardware security deals with the vulnerabilities in the handling of hardware. It is important to protect the hardware from being stolen or surreptitiously replaced. Hardware security can be divided into physical security and emanation security.

Physical Security

Physical security deals with protection of computer hardware and associated equipment, such as, computers, servers, networks, connectivity and peripheral equipment, etc. from external physical threats, such as tampering, theft, earthquakes, water, etc. All equipment handling or containing sensitive information needs to be protected and there must be no possibility for an intruder to access these devices. This can be done by monitoring or restricting the individuals entering the secured areas. 

Emanation Security

Emanation security deals with protection against spurious signals emitted by electrical equipments in the system, such as electromagnetic emission (from displays), visible emission (displays may be visible through windows) and audio emission (sounds from printers, etc).

Information Security

Information security deals with the protection of objects from vulnerabilities present in the architecture of your computer system -- in software, in the hardware and in the combination of software and hardware. 

Information security can be divided into computer security and communication security.

Computer Security

Computer security means protection of objects/equipments against exposures and against attacks making use of vulnerabilities in the system architecture. It deals with a wide variety of problems such as how the access control mechanism should work, how programs inside the computer should act to enforce the security policy, what hardware mechanisms the operating system needs (like virtual memory, etc), what encryption mechanisms to select, etc.

Communication Security

Communication security involves the protection of data and information during transmission. When the information is exchanged, either between networks or locally within a computer, an active attack can modify, retransmit, reorder or destroy information. Communication security issues are implemented by the use of passwords, encryption tools, etc, which deny unauthorized persons from intercepting the information.

Administration Security

Administration Security covers issues like protection of information from vulnerabilities caused by users and threats against vulnerabilities in the security organization. Administration security can be divided into personnel security and operation security.

Personnel Security

Personnel security deals with procedures for ensuring that personnel in the organization can be trusted to comply with security policies. In general, authorized users are a greater threat than external attackers. The personnel responsible for maintaining security in a system present even bigger threat if they abuse their privileges. Protection mechanisms (or at least methods limiting the damages) against such users are necessary. The reasons because of which a user may have to abuse his or her privileges are:

� An external attacker may convince the user to perform an attack (bribes, threats, cheating, etc),

� There can be a personal gain such as money.

� It can be an intellectual challenge.

� It can be revenge/avenge with company, etc.

Personnel security issues also include protection against exposures arising from authorized users, for example when a user sends confidential mail to the wrong person or when a user forgets to log out. Personnel security mechanisms can be improved by educating the users about the importance of maintaining security, to move sensitive information away from certain systems, to restrict privileges to users, to have supervisory controls, etc.

Operation Security

Operation security regulates how all the other forms of security should be implemented and how the system should be operated. It deals with ways of enforcing the rules stated in the security policy, what actions to take when security violations are detected in the system, what recovery mechanisms to implement, etc. It is important that persons maintaining security are informed about events that cause security violations in other systems, and that they continuously update and modify their own system to reach the desired level of security, which can be done by regular updating, changes and modifications of the mechanisms enforcing security.