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
 RSA
( Public Key Cryptography)
(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
Ticket
Granting
Service
Kerberos
(1) request/receive TGS ticket
Client
(2) request/receive server ticket
(3) request service
Server
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
Firewall
Protected
Network
Socksified
user app asks
SOCKS daemon for
circuit
Internet
SOCKS daemon
on firewall parses
request, checks
access control
rules, and makes
connection (proxy);
copy data back in through
firewall.
Target of
communication
sends information
back through SOCKS
daemon, which routes it
to the user desktop.