SECURITY ISSUES IN NETWORKS WITH INTERNET ACCESS

PRESENTED BY

Sri Vallabh

Aida Janciragic

Sashidhar Reddy

Topics of Discussion

• Principles for secure networking

• Internet Vulnerabilities

• Security building blocks

Internet Security

• Why do we need to study security in the internet? Here are some reasons …– Computer networks have lots of vulnerabilities and

threats

– A hacker can log into my machine remotely and destroy the information

– A malicious program can wipe out data on hundreds of computers causing huge losses

Principles for Secure Networking

• Questions to consider– What are we trying to protect?– What operations are authorized?– What is security parameter?

Principles continued…

• Know the configuration of the network hardware and software

• Know the vulnerabilities of the configuration• Know the threats and consider it in relation to the

vulnerabilities to asses the risk• Authenticate and authorize the accessto network

resources

Principles Continued..

• Maintain audit logs

• Have a plan to detect and respond to security incidents

• Ensure individual accountability

The Networks of TwoHands Corporation

• TwoHands corporation develops, produces, and markets specialized gloves used in waste disposal and other safety related applications

• The corporation has a Headquarters,a Research Lab,several factories and warehouses in different parts of the country

Continued…

• Let us discuss the five stages of development in TwoHands Networks and consider in each stage the problems associated with the network and the possible remedies

Stage1:Private Networks Only

Security Problems

1. Any user can access network traffic

2. Diskette drives on the client workstations

3. PCs with modem connections

4. Insufficient training to authorized users

Continued…

Possible Countermeasures1. Introduction of an authentication system for each user2. Installation of virus detection software and configuration monitors3. Installation of temper resistant hardware4. Security awareness training for authorized users

Stage 2:Private Networks plus Read-only Web Server

Security Problems

1. All the problems in stage 1

2. Denial of service attack

3. Unauthorized change to data on web server

4. Web address spoofing

Continued…

Possible Countermeasures

1. Use a reliable web server package

2. Keep abreast of the advisories provided by CERT(Computer Emergency

Response Team), FIRST(Forum of Incident Response Teams)

3. Proper maintenance of web server

Stage 3:Private Nets Plus Forms-Based WWW Server

Security Problems

1. Compromise of order information

2. Spoofing of order information

3. Loss of control over the web site

4. Customer information stored on ISP host.

Continued…

Possible Countermeasures

1. Using a secure web server like HTTP

2. Double checking the CGI scripts

3. Customer authentication

Stage 4:Internet Service through Firewall with Forms-Based WWW Server

Security Problems

1. Attacks on internal systems via misconfigured firewalls

2. Importing of malicious software or exporting of sensitive information via properly configured firewall

3. Compromise of identity of correspondents

4. Back doors into internal networks

Continued…

Possible Countermeasures

1. Proper firewall configuration

2. Vigilant management of firewall and the website

3. Provide proper awareness of security to the internal users

Stage 5:Virtual Private Networks

Security Problems1. Contamination of internal database via

actions of cooperating companies2. Service delays/denial for intranet traffic due to Internet/ISP problems3. Compromise or delay of intranet traffic due to crypto mismanagement4. Compromise of internal traffic patterns

Continued…

Possible Countermeasures

1. Using proper encryption methodology

2. Avoid same company as ISP all the sites

Network Security Policy and Services

• For any level of network security to be established and maintained we need to understand:

• what assets we need to protect • against what threats • to what degree

• identify the elements of security policies appropriate for networks• construct a security policy to meet the needs of network• decide on means for enforcing the policy

Network security services

• confidentiality (protection against eavesdropping) • integrity (protection against data modification)

• authentication (assurance that the source of the data is accurately identified to the recipient)

• non-repudiation (inability of the sender to disavow data the recipient receives)

Vulnerabilities

• Network

• Sniffing• War Dialing

• Protocol

• Data-link-layer security• Network-layer security• Transport-layer security• IP origin forgery

Above the application layer

• System access control and authorization data structures• Malicious Software• Hidden Application Features

Types of Encryption Algorithms

Symmetric DES ( Digital Encryption Standard)

Asymmetric ( Public Key Cryptography)

RSA (Rivest Shamir Adleman)

DES

RSA

Authentication

Cryptographic Hash Functions

MAC (Message Authentication Code)

Digital Signatures

Security in TCP/IP Protocol Stack

Application Layer Encryption

Session Encryption

IP Layer Encryption

Relative Location of Security in TCP/IP Protocol Stack

SSL Protocol Operation

IP Security Scenario

The Kerberos Architecture

Kerberos

Client

TicketGrantingService

Server

(1) request/receive TGS ticket (2) request/receive server ticket

(3) request service

Intrusion Detection

Network Based Network Security Monitor, Network

IDS, Net Ranger, Tripwire etc…

Host Based Probes of host ports, password guessing

etc…

Taxonomy of Malicious Programs

Security Management Tools

SATAN (Security Analysis Tool for Auditing Networks)

ISS (Internet Security Scanner)

Tiger Crack Snoop

Firewall

• Firewall : a method used to prevent unauthorized access to a private network

InternetInternet

Trust

Types of Firewalls

SOCKS

Target ofcommunicationsends informationback through SOCKSdaemon, which routes itto the user desktop.

ProtectedNetwork

InternetInternet

Firewall

SOCKS daemonon firewall parsesrequest, checks access controlrules, and makesconnection (proxy);copy data back in throughfirewall.

Socksifieduser app asksSOCKS daemon forcircuit