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 Countermeasures 1.Introduction of an authentication system for each user 2.Installation of virus detection software and configuration monitors 3.Installation of temper resistant hardware 4.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 Problems 1.Contamination of internal database via actions of cooperating companies 2.Service delays/denial for intranet traffic due to Internet/ISP problems 3.Compromise or delay of intranet traffic due to crypto mismanagement 4.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 Ticket Granting Service 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 Internet Trust

Types of Firewalls

SOCKS Target of communication sends information back through SOCKS daemon, which routes it to the user desktop. Protected Network Internet Firewall SOCKS daemon on firewall parses request, checks access control rules, and makes connection (proxy); copy data back in through firewall. Socksified user app asks SOCKS daemon for circuit