Lecture Information systems security - Chapter 1: General security concepts

The content in chapter 1: Understanding information security, understanding the goals of information security, comprehending the security process, authentication issues to consider, distinguishing between security topologies.

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General Security Concepts

v Understanding Information Security

v Understanding the Goals of Information Security

v Comprehending the Security Process

v Authentication Issues to Consider

v Distinguishing between Security Topologies

Information Security

v Security?

v Physical security of servers and workstations

v Protecting data from viruses and worms or from hackers and miscreants

v The capability to restore files if a user accidentally deletes them

v …

v Problems with security:

v It is next to impossible for everyone to agree on what it means

v We don’t really mean that we want things to be completely secured

v While everyone wants security, no one wants to be inconvenienced by it

Security Triad

Securing the Physical Environment

v Protecting your assets and information from physical access by unauthorized persons

v Threats often present themselves as service technicians, janitors, customers, vendors, or even employees

v Components of physical security:

v Making a physical location less tempting as a target

v Detecting a penetration or theft

v Recovering from a theft or loss of critical information or systems

Examining Operational Security

v Operational security issues include:

v Network access control (NAC),

v Authentication,

v Security topologies after the network installation is complete.

v Daily operations of the network

v Connections to other networks

v Backup plans

v Recovery plans

v In short, operational security encompasses everything that isn’t related to design or physical security in the network

Examining Operational Security

Working with Management and Policies

v Guidance, rules, and procedures for implementing a security environment

v Policies need the support of management to be carried out well

v The issues that must be decided at the management and policy level affect the entire company and can greatly impact productivity, morale, and corporate culture

Working with Management and Policies

v A number of key policies are needed to secure a network The following list identifies some broad areas that require thought and planning:

Administrative Policies

v Administrative policies lay out guidelines and expectations for upgrades, monitoring, backups, and audits

v System administrators and maintenance staff use these policies to conduct business

v The policies must be:

v Specific enough to help the administrative staff keep focused on the business of running the systems and networks

v Flexible enough to allow for emergencies and unforeseen circumstances.

Disaster recovery plans (DRPs)

v Expensive to develop and to test, and it must be kept current

v Takes into consideration virtually every type of occurrence or failure possible

v The key to its success is its completeness

v Many large companies invest huge amounts of money in DRPs, including backup or hot sites

Information Policies

v Refer to the various aspects of information security, including access, classifications, marking and storage, and the transmission and destruction of sensitive information

v Data classification matrix

v Defines various classification levels

v Public: For all advertisements and information posted on the Web

v Internal: For all intranet-type information

v Private: Personnel records, client data, and so on

v Confidential: Public Key Infrastructure (PKI) information and other items restricted to all but those who must know them

Security Policies

v Define the configuration of systems and networks

v Security policies also define computer room and data center security as well as how identification and authentication (I&A) occurs

v Things covered:

v Determine how access control, audits, reports and network connectivity are handled.

v Encryption and antivirus software

v Establish procedures and methods used for password selection, account expiration, failed logon attempts, and related areas

Software Design Requirements

v Software design requirements outline what the capabilities of the system must be

v A software design policy should be specific about security requirements

v If the design doesn’t include security as an integral part

of the implementation, the network may have vulnerabilities

Usage Policies

v Cover how information and resources are used

v Include statements about privacy, ownership, and the consequences of improper acts

v Usage policies should also address how users should handle incidents

User Management Policies

v Identify the various actions that must occur in the normal course of employee activities

v These policies must address how new employees are added to the system as well as managed

v A user may acquire administrative privileges to the system by accident

v Understanding Information Security

v Understanding the Goals of Information Security

v Comprehending the Security Process

v Authentication Issues to Consider

v Distinguishing between Security Topologies

Goals of Information Security

v Prevention: preventing computer or information violations from occurring

v Detection: identifying events when they occur

v Response: developing strategies and techniques to deal with an attack or loss

v Understanding Information Security

v Understanding the Goals of Information Security

v Comprehending the Security Process

v Authentication Issues to Consider

v Distinguishing between Security Topologies

Comprehending the Security Process

v Security is a combination of three Ps: processes,

procedures, and policies.

v There are several parts to this process

v Appreciating Antivirus Software

v Implementing Access Control

v Authentication

Access Control

v Mandatory Access Control (MAC):

v A static model that uses a predefined set of access privileges for files on the system.

v The system administrators establish these parameters and associate them with an account, files

v MAC uses labels to identify the level of sensitivity that applies to objects.

v When a user attempts to access an object, the label is examined

to see if the access should take place or be denied.

v One key element to remember is that when mandatory control is applied, labels are required and must exist for every object., or resources.

v Something you know, such as a password or PIN

v Something you have, such as a smart card or an identification

device

v Something physically unique to you, such as your fingerprints

or retinal pattern

v Commonly used

v A server or certificate authority (CA) can issue a certificate that will be accepted by the challenging system

v Certificate Practice Statement (CPS) outlines the rules used for issuing and managing certificate

v Certificate Revocation List (CRL) lists the revocations that must be addressed (often due to expiration) in order

to stay current

Certificates

Challenge Handshake Authentication

Protocol

v CHAP doesn’t use a user ID/password mechanism

v The initiator sends a logon request from the client to the server

v The server sends a challenge back to the client

v The challenge is encrypted and then sent back to the server

v The server compares the value from the client

v If the information matches, grants authorization.

v If the response fails, the session fails, and the request phase starts over

Challenge Handshake Authentication Protocol

v Originally designed by MIT

v Allows for a single sign-on to a distributed network

v Key Distribution Center (KDC) authenticates the

principle (which can be a user, a program, or a system)

and provides it with a ticket

v After this ticket is issued, it can be used to authenticate against other principles This occurs automatically when

a request or service is performed by another principle

v KDC can be a single point of failure

Kerberos

Multi-Factor Authentication

v Two or more access methods are included as part of the authentication process

Mutual Authentication

v Two or more parties authenticate each other

v Mutual authentication ensures that the client is not unwittingly connecting and giving its credentials to a rogue server; which can then turn around and steal the data from the real server

v Commonly, mutual authentication will be implemented when the data to be sent during the session is of a critical nature – such as financial or medical record

Password Authentication Protocol (PAP)

v One of the simplest forms of authentication

Security Tokens

v A small piece of data that holds a sliver of information about the user

Smart Cards

v A type of badge or card that gives you access to resources, including buildings, parking lots, and computers

v Contains information about one’s identity and access privileges

v Each area or computer has a card scanner or a reader in which you insert your card

v Smart Cards often also require the use of a small password called a PIN (personal identification number); which further secures the smart card if lost by the true card holder, so that it cannot be used by someone else

to gain access to data and resources

Smart Card Authentication Process

Username/Password

v Understanding Information Security

v Understanding the Goals of Information Security

v Comprehending the Security Process

v Authentication Issues to Consider

v Distinguishing between Security Topologies

Authentication Issues

v Capabilities of people who will be working with policies

v Be wary of popular names or current trends that make certain passwords predictable

v Distinguish between identification process and authentication process

v Understanding Information Security

v Understanding the Goals of Information Security

v Comprehending the Security Process

v Authentication Issues to Consider

v Distinguishing between Security Topologies

Setting Design Goals

v Confidentiality: Prevent or minimize unauthorized

access to and disclosure of data and information

v Integrity: Making sure that the data being worked with is

the correct data

v Availability: Protect data and prevent its loss

v Accountability: Who owns the data or is responsible for

making sure that it’s accurate

Creating Security Zones

v Four most common security zones:

v Internet

v Intranet

v Extranet

v Demilitarized zone (DMZ)

The Internet – Typical LAN connection

The Internet – Cisco Network Diagram

Intranets

Extranets

Demilitarized Zone (DMZ)

v A demilitarized zone (DMZ) is an area where you can place a public server for access by people you might not trust otherwise

v By isolating a server in a DMZ, you can hide or remove access to other areas of your network

v Use firewalls to isolate your network

Demilitarized Zone (DMZ)

v Today’s x86 computer hardware was designed to run a single operating system and a single application, leaving most machines vastly underutilized

v Virtualization lets you run multiple virtual machines on a single physical machine, with each virtual machine sharing the resources of that one physical computer across multiple environments

v Different virtual machines can run different operating systems and multiple applications on the same physical computer

Why Virtualize?

v Get more out of your existing resources

v Reduce datacenter costs by reducing your physical infrastructure and improving your server to admin ratio

v Increase availability of hardware and applications for improved business continuity

v Gain operational flexibility

v Improve desktop manageability and security

Virtual Local Area Networks

v A virtual local area network (VLAN) allows you to create groups of users and systems and segment them on the network

v This segmentation lets you hide segments of the network from other segments and thereby control access

v You can also set up VLANs to control the paths that data takes to get from one point to another A VLAN is a good way to contain network traffic to a certain area in a network

Virtual Local Area Networks

Network Address Translation

v Originally, NAT extended the number of usable Internet addresses

v Allow an organization to present a single address to the Internet for all computer connections

v The NAT server provides IP addresses to the hosts or systems in the network and tracks inbound and outbound traffic

Network Address Translation

v In most tunnels, the data passed through the tunnel appears at the other side as part of the network

v Tunneling protocols usually include data security as well

as encryption Several popular standards have emerged for tunneling, with the most popular being the Layer 2 Tunneling Protocol (L2TP)

v Tunneling sends private data across a public network by placing (encapsulating) that data into other packets Most tunnels are virtual private networks (VPNs)

Tunneling