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Security overview

Unit objectives Discuss network security Discuss security threat trends and

their ramifications Determine the factors involved in

creating a secure network strategy Control access to a Windows 2000

server

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Topic A

Topic A: Introduction to network security

Topic B: Understanding security threats

Topic C: Creating a secure network strategy

Topic D: Windows 2000 server access control

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Network security defined

Network security:– Process by which digital information

assets are protected

Goals of network security are to:– Protect confidentiality– Maintain integrity– Assure availability

Assessing risk– Identify threats– Reduce vulnerabilities

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Information Security

Tasks of guarding digital information, which is typically processed by a computer, stored on a magnetic or optical storage device (such as a hard drive or DVD), and transmitted over a network.

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An isolated computer

What security threat do we have?

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Connected to the Internet

What security threat do we have?

The InternetThe Internet

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Information vs. Network

Most of the threat are from the network, that is why we chose the name “Network Security” instead of “Information Security”.

But the intention is to secure the information.

Information is an asset that must be protected.

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Financial Loss

Without adequate protection or network security, a company is highly susceptible to a financial loss.

The fear of security breach can cause financial loss as an actual breach.

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Each attack costs $213,000

After an attack on information security, clean-up efforts divert resources, such as time and money away from normal activities

A Corporate IT Forum survey of major corporations showed:– Each attack costs a company an average

of $213,000 in lost man-hours and related costs

– One-third of corporations reported an average of more than 3,000 man-hours lost

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Information Security

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Threat vs. Vulnerability

A threat is defined as any activity that poses a danger to our information.

A vulnerability is a weakness in a system, such as misconfigured hardware or software, poor design, or end-user carelessness.

Threats exploit vulnerabilities in order to gain unauthorized access to a network.

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Effect of Evolving technologies

Mainframes LANs Firewalls Extranets Security systems

– Intrusion detection– Authentication– Authorization– Vulnerability assessment

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Security build Trust

Security is critical for all types of Internet business.

By protecting systems from intrusion and corruption, security technologies help companies build trust

A trust that information is protected and transactions are reliable

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Securing means Managing risk

Users can perform only authorized tasks

Users can obtain only authorized information

Users cannot damage data, applications, or operating environment

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Errors and Equipment Failures

Though “security” means protection against malicious attacks by outsiders.

Security also involves controlling the effects of errors and equipment failures.

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Goals of network security - CIA

The goal of implementing network security is to maintain an acceptable level of confidentiality, integrity and availability of information.

Confidentiality– Protection of data from unauthorized disclosure

to a third party

Integrity– Assurance that data is not altered or destroyed

in an unauthorized manner

Availability– Continuous operation of computing systems

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Topic B

Topic A: Introduction to network security

Topic B: Understanding security threats

Topic C: Creating a secure network strategy

Topic D: Windows 2000 server access control

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Price of Intrusion

Corporate espionage, – FBI estimates up to $100 billion loss

Identity theft – up to 700,000 Americans

Computer Viruses– up to $13.2 billion in 2001

– Lost revenues– Lost prestige– Lost productivity

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CERT Computer Emergency Response Team (CERT)

security organization compiles statistics regarding number of reported attacks, including:– Speed of attacks– Sophistication of attacks– Faster detection of weaknesses– Distributed attacks– Difficulties of patching

http://www.cert.org/ Established in 1988, the CERT® Coordination

Center (CERT/CC) is a center of Internet security expertise, located at the Software Engineering Institute, a federally funded research and development center operated by Carnegie Mellon University.

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Sources of threats

Compromising of each of these three security goals can cost organization either – directly or – indirectly

There are four causes for compromised security:– Technology weaknesses– Configuration weaknesses– Policy weaknesses– Human error or malice

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Technology weaknesses

TCP/IP Operating systems Network equipment

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TECHNOLOGY WEAKNESSESare a part of each technology

TCP/IP

A communication protocoldesigned as an open standard.

Application

Presentation

Session

Transport

Network

Data Link

Physical

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TECHNOLOGY WEAKNESSESare a part of each technology

Operating Systems

Windows, Linux, Unix,

Each operating system has issues.

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TECHNOLOGY WEAKNESSESare a part of each system

Networking equipment

All networking equipment must be protected!

Passwords Firewalls

Protocols Authentication

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Configuration weaknesses

Unsecured accounts System accounts with easily guessed

passwords Misconfigured Internet services Unsecured default settings Misconfigured network equipment Trojan horse programs Vandals Viruses

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Policy weaknesses

Lack of a written security policy Politics High turnover Concise access controls not applied Software and hardware installation

and changes do not follow policy Proper security Nonexistent disaster recovery plan

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Human error and malice

Accident Ignorance Workload Dishonesty Impersonation Disgruntled employees Snoops Denial-of-service attacks

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Topic C

Topic A: Introduction to network security

Topic B: Understanding security threats

Topic C: Creating a secure network strategy

Topic D: Windows 2000 server access control

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Network security strategies

Achieve the state where any action that is not expressly permitted is prohibited

Address both internal and external threats

Define policies and procedures Reduce risk across perimeter security,

the Internet, intranets, and LANs

(continued)

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Network security strategies, continued

Human factors Knowing your weaknesses Limiting access Achieving security through persistence Physical security Perimeter security

(continued)

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Secure network strategy, cont’d

Firewalls Web and file servers Access control Change management Encryption Intrusion detection systems (IDS)

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Topic D

Topic A: Introduction to network security

Topic B: Understanding security threats

Topic C: Creating a secure network strategy

Topic D: Windows 2000 server access control

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Access control

Restricts access to a resource Security levels

– Identify– Authenticate– Authorize

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MAC, DAC and RBAC

Mandatory access control (MAC)– Non-discretionary control used in high-

security locations

Discretionary access control– Allows the owner of a file to dictate who

can access the file and to what extent

Role-based access control – Access is based on the role a user plays

in the organization

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Unit summary

Discussed network security Discussed the security threat trends

and their ramifications Discussed the goals of network

security and determined the factors involved in a secure network strategy

Discussed methods of access control and their implementation on a Windows 2000 server