web security for network and system administrators1 chapter 1 introduction to information security

Web Security for Network and System Administrators 1

Chapter 1

Introduction to Information Security

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Objectives

In this chapter, you will:• Define basic security concepts• Begin to assess security risks• Outline a security policy• Locate information security resources

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Basic Security Concepts

• Confidentiality – only authorized individuals can access data

• Integrity – data changes are tracked and properly controlled

• Availability – systems are accessible for business needs

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Basic Security Concepts

• Physical security – protect people, equipment, and facilities

• Privacy – critical data is not released to the wrong people

• Marketplace perception – the way the company is perceived by customers, partners, and competitors

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Assessing Risk

• Check existing security policies and processes

• Analyze, prioritize, and categorize resources by determining: total cost of ownership, internal value, and external value. – TCO refers to the total monetary and labor costs

calculated over a specific time period – Internal value refers to the monetary assessment of the

importance of a particular asset to the internal working of a company

– External value refers to the money or another commodity that the asset brings to the company from external sources

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Assessing Risk

• Consider business concerns through the annualized loss expectancy (ALE = SLE * ARO)– Single loss expectancy (SLE) is equal to the

asset’s value times the exposure factor (EF)• Asset value = TCO + internal value + external value• EF is the percentage of asset loss that is expected

from a particular threat

– Annualized rate of occurrence (ARO) is the estimated frequency with which a particular threat may occur each year

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Assessing Risk

• Evaluate existing security controls to determine what controls are deployed and effective

• Leverage existing management and control architecture to build a persuasive business case for, or against, implementing new security controls

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Building a Security Policy

• A security policy has the following three important benefits:– Communicates a common vision for security

throughout a company

– Represents a single easy-to-use source of security requirements

– Exists as a flexible document that should be updated at least annually to address new security threats

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Building a Security Policy

An organization’s security policy should cover the following:

• Foreword: Purpose, scope, responsibilities, and penalties for noncompliance

• Physical security: Controls to protect the people, equipment, facilities, and computer assets

• User ID and rights management: Only authorized individuals have access to the necessary systems and network devices

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Building a Security Policy

An organization’s security policy should cover the following:

• Network security: Protect the network devices and data in transit

• System security: Necessary defenses to protect computer systems from compromise

• Testing: Authorized security tools and testing • Auditing: Procedures to periodically check

security compliance

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Building a Security Policy Foreword

• Purpose: Why is this policy being established?• Scope: What people, systems, software,

information, and facilities are covered?• Responsibilities: Who is responsible for the

various computing roles in a company?• Compliance: What are the penalties for

noncompliance? Which organization is responsible for auditing compliance?

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Building a Security Policy Physical Security

• Human threats: theft, vandalism, sabotage, and terrorism

• Building damage: fire, water damage, and toxic leaks

• Natural disasters: floods, hurricanes, and tornadoes

• Infrastructure disruption: loss of power, loss of HVAC, and downed communication lines

• Equipment failure: computer system damage and network device failure

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Building a Security Policy User ID and Rights Management

• User Account Creation, Deletion, and Validation – manage user accounts

• Password Policies – manage password parameters

• Access Controls - determine who gets what access to what

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Building a Security Policy Network Security

• Specific timeframes for changing passwords on the network devices

• Use of secure network protocols• Firewalls at specific chokepoints in a network

architecture• Use of authentication servers to access network

devices

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Building a Security Policy System Security

• The systems section is used to outline the specific settings required to secure a particular operating system or application– For example, for Windows NT 4.0, it may be a

requirement that every logical drive be installed with NTFS

– For a particular UNIX flavor, shadow password files may be required to hide user IDs and passwords from general users

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Building a Security Policy Testing and Auditing

• Specify requirements for vulnerability scanners, compliance checking tools, and other security tools run within the environment

• Require auditing logs on specific devices, periodic self-audits performed by the system administrators, and the use of security compliance checking tools

• Specify corporate auditing requirements, frequencies, and organizations

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Security ResourcesSecurity Certifications

• CISSP• SSCP• GIAC• CISA• CIW Security Professional

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Security ResourcesWeb Resources

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Summary

• The CIA triad categorizes aspects of information that must be protected from attacks: confidentiality, integrity, and availability.

• The PPP triad depicts security, privacy, and marketplace perception as three additional abstract concepts that should drive security efforts.

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Summary• The first step in creating an effective security policy is to perform a

risk assessment within the environment. A risk assessment consists of five steps:– Check for existing security policies and processes– Analyze, prioritize, and categorize resources– Consider business concerns– Evaluate existing security controls– Leverage existing management and control architecture

• To estimate potential financial loss from security threats, the following formula works well by accounting for the most important cost factors associated with security: ALE = SLE * ARO.

• A security policy has three major benefits. It:– Communicates a common vision for security throughout a

company– Represents a single easy-to-use source of security

requirements– Exists as a flexible document that should be updated at least

annually to address new security threats

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Summary• An effective security policy includes security requirements in the

following areas:– Physical security– User ID and rights management– Systems– Network– Security tools– Auditing

• There are a number of security-related certifications to help security professionals quantify their knowledge on a resume.

• Every security professional must stay current about the latest threats through Web resources, mailing lists, and printed materials.