Security
Securing IS
SECURITY:
Deter
Detect
Minimize
Investigate
Recover
Security Risks
Internal
External
Accidental
Destruction
Alteration
Access
Intentional
Threats
Disaster and breakdowns
Access and disclosure
Alteration or destruction
Improper use
RISK ASSESSMENT
P1
P2
L
Probability of attack
Probability of success
Cost of Loss
Expected Loss = P1 * P2 * L
Minimize Threat Categories
Security Policy
Security is always a cost to efficiency. It
must be promoted to be effective.
From the top
Before installing hardware
Politically charged
Writing a Security Policy
Assess the types of risks
Identify vulnerabilities
Analyze user needs
Write the policy
Develop change procedures
Plan implementation
Implement
Elements of Risk
Asset
Threat
Access
Administrative Controls:
Limit the Threat
Standards, rules, procedures and
discipline to assure that personnel
abide by established policies.
Includes segregation of functions.
Administrative Controls
Security organization
Audits
Risk assessment
Administrative standards and procedures
Protecting the Assets
Resource management
Disaster recovery
System segregation
Resource Management
Backup planning
Job scheduling
Redundant design
Selective decoupling
Disaster Management
Redundancy and fault tolerant systems
Backups and off site storage
Hot and cold sites
Planning and procedures
Elements of Risk
Asset
Threat
Access
Vulnerabilities
Servers
Securing operating systems and applications
Networks
Access protection from snooping, attacks,
spoofing
Clients and modems
User verification for PCAnywhere etc.
Viruses
Operating Systems
UNIX
Novell Netware
Windows and Windows NT
Secure Operating Systems
U.S. Government Certification
A1, B1, B2, B3, C1, C2 (most commercial
systems), D
Ease of use
CERT (Computer Emergency Response
Team) www.cert.org
Top 12 SecurityRisks
1. Hosts run unnecessary
services
3. Information leakage through
network service programs
4. Misuse of trusted access
5. Misconfigured firewall access
lists
7. Misconfigured web servers
10.Inadequate logging,
monitoring or detecting
Top 12 Security Risks
2. Unpatched, outdated or
default configured software
6. Weak Passwords
8.Improperly exported file
sharing services
9. Misconfigured or unpatched
Windows NT servers
11.Unsecured remote access
12.Lack of comprehensive
policies and standards
Tools
Firewalls
Network partitioning and routers
Encryption
Testing tools
Consultants
Firewall functions
Packet Filter: Blocks traffic based on IP address and/or
port numbers.
Proxy Server: Serves as a relay between two networks,
breaking the connection between the two.
Network Address Translation (NAT): Hides the IP
addresses of client stations in an internal network by
presenting one IP address to the outside world.
Stateful Inspection: Tracks the transaction in order to
verify that the destination of an inbound packet matches
the source of a previous outbound request. Generally can
examine multiple layers of the protocol stack.
Firewall Operation
Firewall
Operation
1. A router sits between two
networks
2. A programmer writes an access control list,
which contains IP addresses that can be allowed
onto the network.
3. A message gets sent to the router. It checks the
address against the access control list. If
address the is on the list, it can go through.
4. If the address isn't on the list, the message is
denied access to the network.
Encryption
Keys and key length
Public key/private key
Processing problems
Location
Application
Network
Firewall
Link
Encryption
Techniques
How Public Encryption
Works
1. Sue wants to send a
message to Sam, so she
finds his public key in a
directory.
2. Sue uses the public key
to encrypt the message
and send it to Sam.
3. When the encrypted
message arrives, Sam
uses his private key to
decrypt the data and read
Sue's message.
Encryption at the Firewall
Authentication
Passwords
“Credit” cards
Biometrics
Isolation
Remote location verification
Biometrics: how it works
 Users "enroll" by having their fingerprints, irises, faces,
signatures or voice prints scanned.
 Key features are extracted and converted to unique
templates, which are stored as encrypted numerical data.
 Corresponding features presented by a would-be user are
compared to the templates in the database.
 Matches will rarely be perfect, and the owners of the
system can vary a sensitivity threshhold so as to minimize
either the rate of false rejections, which annoy users, or
false acceptances, which jeopardize security. This offers far
more flexibility than the binary "Yes" or "No" answers
given by password technologies.
Common biometric
techniques and how they rate
INTRUSIVNESS EFFORT
Dynamic signature Excellent
verification
Good
Face geometry
Fair
Finger scan
ACCURACY COST
Fair
Fair
Excellent
Good
Good
Fair
Good
Good
Good
Hand geometry
Passive iris scan
Fair
Poor
Good
Excellent
Fair
Excellent
Fair
Poor
Retina scan
Voice print
Poor
Very good
Poor
Poor
Very Good
Fair
Fair
Very Good
International Biometric Group, New York
as reported in Computerworld, Quick Study: Biometrics, 10/12/98
Security: The expense
that keeps on costing,
By Erik Sherman, June 2000
Lessons learned about properly securing
your company.
Train employees to act in secure ways
Use security professionals to perform an
audit
Provide the necessary resources
Physically secure servers
Use the appropriate degree of security
Security