Introduction: Overview of computer security

Computer Security:  Security applied to an automated information system to attain the applicable objectives of preserving the integrity, availability, and confidentiality of information system resources, i.e protection of computer systems and information from harm, theft and unauthorized use.

Computer Security is mainly concerned with three main areas: 

# Confidentiality

# Integrity

# Availability

CIA Triangle (Triad)

# It is simple but widely-applicable security model.

# The CIA Triad refers to the 3 goals of information security of the organization’s system, network and data. 

# They are, “ Confidentiality, Integrity & Availability “.

Confidentiality

• Confidentiality is roughly equivalent to privacy,  that means that only the authorized individuals/systems can view sensitive or classified information.
• The data being sent over the network should not be accessed by unauthorized individuals. 
• The attacker may try to capture the data using different tools available and gain access to your information. 
• Data encryption is a common method of ensuring confidentiality.
• Another way to protect your data is through a VPN tunnel. VPN stands for Virtual Private Network and helps the data to move securely over the network.

Integrity

• Integrity is protecting information from being modified by unauthorized parties.
• The ability to ensure that data is an accurate and unchanged representation of the original secure information, Well, the idea here is making sure that data has not been modified.
• Corruption of data is a failure to maintain data integrity. Corruption can occur when information is being compiled, stored, or transmitted. 
• To check if our data has been modified or not, we make use of a hash function such as SHA (Secure Hash Algorithm) and MD5(Message Direct 5).

Availability

• Availability of information refers to, ensuring that authorized users are able to access the information when needed.
• This means that the computing systems used to store and process the information, the security controls used to protect it, and the communication channels used to access it must be functioning correctly.
•  Information can be erased or become inaccessible, resulting in “loss of availability.”
• Ensuring availability also involves preventing denial-of-service attacks, such as a flood of incoming messages to the target system, essentially forcing it to shut down.

To make information available to those who need it and who can be trusted with it, organizations use authentication and authorization. 

# Authentication is proving that a user is a person he or she claims to be. 

# Authorization is the act of determining whether a particular user (or computer system) has the right to carry out a certain activity, such as reading a file or running a program. 

# Authentication and authorization go hand in hand. 

# Users must be authenticated before carrying out the activity they are authorized to perform. 

# Security is strong when the user cannot later deny that he or she performed the activity. 

This is known as nonrepudiation.    

#  Accountability ( Tracing activities of an individual on a system) also supports non-repudiation 

# These concepts of information security also apply to the term information security.

Challenges of Computer Security

• Computer security is not as simple as it might first appear to the novice. But the mechanisms used to meet the requirements such as confidentiality, integrity, and availability can be quite complex, and understanding them may involve rather a subtle reasoning (mental keenness).
• Potential attacks on developing a particular security mechanism or algorithm's security features.
• The procedures used to provide particular services are often counterintuitive (does not happen in the way you would expect it to)
• It is necessary to decide where to use the various security mechanisms in terms of physical placement (e.g., at what points in a network are certain security mechanisms needed) & in a logical sense (e.g., at what layer or layers of architecture such as TCP/IP should mechanisms be placed)
• Security requires regular, even constant, monitoring, and this is difficult in today’s short-term, overloaded environment.

Components of Information System

Components of the information system are as follows:

# Hardware: Including computer systems and other data processing, data storage, and data communications devices.

# Software: Including the operating system, system utilities, and applications. These are used to control and coordinate the hardware components and for analyzing and processing of the data.

# Data: Including files and databases, as well as security-related data, such as password files.

# Network: Refers to the local and wide area network communication links, bridges, routers, and so on. These resources facilitate the flow of information in the organization.

# People: Every system needs people if it is to be useful, probably the component that most influences the success or failure of information systems. This includes "not only the users, but those who operate and service the computers, those who maintain the data, and those who support the network of computers."

# Procedures: The policies that govern the operation of a computer system.

Need for Information Security

The purpose of information security is to ensure the key Objectives, i.e.

# Confidentiality 

# Integrity

# Availability 

Thus preventing & minimising the impact of security incidents.

The major needs for security in an organization are,

# Protecting the functionality of the organization

# Enabling the safe operation of applications

# Protecting the data that the organization collect and use

# Safeguarding technology assets in organizations

Protecting the functionality of the organization

• Implementing information security in an organization can protect the technology and information assets, by preventing, detecting, and responding to threats.  
• The decision-maker in organizations must set policy and operates their organization in keeping with the complex, efficient, and capable applications.

Enabling the safe operation of applications

• The modern organization needs to create an environment that safeguards the application, particularly those application that serves as important elements of the infrastructure of the organization.

Protecting the data that the organization collect & use

• Data in the organization can be in two forms that are either in rest or in motion, the motion of data signifies that data is currently used or processed by the system. 
• The attacker may try to corrupt the data values which affects the integrity of the data.

Safeguarding technology assets in organisations

•  The organization must add secure infrastructure services based on the size & scope of the organization. 
• Additional security services may be needed as the organization expands.

NSTISSC SECURITY MODEL

National Security Telecommunications & Information systems security committee’ document

# It is now called the National Training Standard for Information security professionals. 

# While the NSTISSC model covers the three dimensions of information security, it omits a discussion of detailed guidelines and policies that direct the implementation of controls.

# The 3 dimensions of each axis become a 3x3x3 cube with 27 cells representing areas that must be addressed to secure today’s Information systems.

# To ensure system security, each of the 27 cells must be properly addressed during the security process.

 # For example, the intersection between technology, Integrity & storage areas requires control or safeguard that addresses the need to use technology to protect the Integrity of information while in storage.