Chapter 02

Developing a Security Policy Chapter 2

Learning Objectives Understand why a security policy is an important part of a firewall implementation Determine the goals of your firewall and incorporate them into a security policy Follow the seven steps to building a security policy Account for situations the firewall can’t handle Define responses to security violations Work with administration to make your security policy work

What Is a Security Policy? A set of organization-level rules governing:   

Acceptable use of computing resources Security practices Operational procedures

Example of a Security Policy

Essential Information in a Security Policy Date last updated Name of office that developed the policies Clear list of policy topics Equal emphasis on positive points (access to information) and negative points (unacceptable policies)

Why Is a Security Policy Important? Essential component of a fully functional firewall 



Defines what needs to be done when firewall is configured Defines intrusion detection and auditing systems that are needed

Minimizes impact of a “hack attack” on:   

Staff time Data loss Productivity

Setting Goals for an Effective Security Policy Describe a clear vision for a secure networked computing environment Be flexible enough to adapt to changes in the organization Be consistently communicated and implemented throughout the organization Specify how employees can and cannot use the Internet Define appropriate and inappropriate behavior as it pertains to privacy and security

Seven Steps to Building a Security Policy       

Develop a policy team Determine organization’s overall approach to security Identify assets to be protected Determine what should be audited for security Identify security risks Define acceptable use Provide for remote access

Develop a Policy Team Members (5-10 people)     

Senior administrator Member of legal staff Representative from rank-and-file employees Member of IT department Editor or writer who can structure and present the policy coherently

Identify one person to be the official policy interpreter

Determine Overall Approach to Security Two primary activities for overall approach:  

Restrictive Permissive

Specific security stances:     

Open Optimistic Cautious Strict Paranoid

Identify Assets to Be Protected Physical assets 

Actual hardware devices

Logical assets 

Digital information that can be viewed and misused

Network assets 

Routers, cables, bastion hosts, servers, firewall hardware and software

System assets 

Software that runs the system (ie, server software and applications)

Example of Assets to Be Protected

Determine What Should Be Audited for Security Auditing 



Process of recording which computers are accessing a network and what resources are being accessed Includes recording the information in a log file

Specify types of communication to be recorded and how long they will be stored Use Tripwire to audit system resources Use a firewall log to audit security events

Auditing with Tripwire

Auditing with a Firewall Log

Determine What Should Be Audited for Security Auditing log files Auditing object access

Identify Security Risks Specify the kinds of attacks the firewall needs to guard against   

Denial of service attacks Disclosure of information due to fraud Unauthorized access

Define Acceptable Use Define acceptable computing and communications practices on the part of employees and business partners Aspects  

E-mail News

Provide for Remote Access Specify acceptable protocols Determine use of Telnet or Secure Shell (SSH) access to internal network from Internet Describe use of cable modem, VPN, and DSL connections to access internal network through the firewall Require remote users to have a firewall on their computer

Accounting for What the Firewall Cannot Do A firewall sandwich or load balancing switches can be compromised by:  





Brute force attack Sending an encrypted e-mail message to someone within the network with a virus attached Employees who give out remote access numbers; unauthorized users can access company network Employees who give out passwords

Other Security Policy Topics Passwords Encryption Restrictions on removable media ASPs Acceptable users

Secure use of office-owned laptop computers Wireless security Use of VPNs Key policy

Defining Responses to Security Violations Gather information on an incident response form Define disciplinary action to be pursued if employees access the Internet improperly Identify who to contact in case of intrusion

Defining Responses to Security Violations

Overcoming Administrative Obstacles

Educating Employees Security User Awareness program Advise workers of expectations and consequences Make policies available on local network

Presenting and Reviewing the Process Keep reports short and concise Give people ample time to respond after policy statement is issued

Amending the Security Policy Change the security policy when: 



The organization makes substantial changes in hardware configuration, or The firewall is reconfigured in response to security breaches

Chapter Summary What a security policy is; why they are important Setting goals that govern how a firewall is configured to protect a network Seven steps to building a security policy Defining responses to attacks and other intrusions Guiding your security policy through corporate bureaucracy to gain management support and achieve security policy goals