Introduction to Major Modules in
Cyber Security
August 30, 2013
Lecture #2
Dr. Bhavani Thuraisingham
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Outline
0 What is Cyber Security?
0 What is C. I. A.?
0 Ten Major Modules of Cyber Security
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Cyber Security
0 Security traditionally has been about CIA (Confidentiality, Integrity,
Availability)
0 Security now also includes areas like Trustworthiness, Quality,
Privacy
0 Dependability includes Security, Reliability and Fault Tolerance
0 Initially the term used was Computer Security (Compusec); it then
evolved into Infosec – Information security – to include data and
networks – now with web its called Cyber Security
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C. I.A.
0 Confidentiality: Preventing from unauthorized disclosure
0 Integrity: Preventing from unauthorized modification
0 Availability: Preventing denial of service
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Ten Major Modules of Cyber Security
0 Information Security and Risk Management
0 Access Control
0 Security Architecture and Design
0 Cryptography
0 Network Security
0 Applications Security (aka Data and Applications Security)
0 Legal Regulations, Compliance and Investigations (aka Digital
Forensics)
0 Physical and Environmental Security
0 Business Continuity Planning
0 Operations Security
0 Not included: Hardware security; Performance Analysis, Ethical
Hacking and Penetration Testing, - - -
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Information Security and Risk Management
0 Security Management
0 Security Administration
0 Organizational Security Model
0 Information Risk Management
0 Risk Analysis
0 Policies, Standards, Guidelines, Procedures
0 Information Classification
0 Layers of Responsibility
0 Security Awareness Training
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Access Control
0 Security Principles
0 Identification, Authentication, Authorization, Accountability
0 Access Control Models
0 Access Control techniques
0 Access Control Administration
0 Access Control Methods
0 Access Control Types
0 Accountability
0 Access Control practices
0 Access Control Monitoring
0 Threats to Access Control
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Security Architecture and Design
0 Computer Architecture
0 Systems Architecture
0 Security Models
0 Security Modes of Operation
0 Systems Evaluation Methods
0 Open vs. Closed Systems
0 Enterprise Architecture
0 Security Threats
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Physical and Environmental Security
0 What is Physical Security
0 Planning Process
0 Protecting assets
0 Internal Support Systems
0 Perimeter Security
0 Other aspects
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Telecommunications and Network Security
0 Open Systems Interconnection Reference Model
0 TCP/IP
0 Types of Transmission
0 LAN Networking
0 Routing Protocols
0 Networking Devices
0 Networking services and protocols
0 Intranets and Extranets
0 Metropolitan Area networks
0 Remote access
0 Wireless technologies
0 Rootkits
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Cryptography
0 History, Definitions and Concepts
0 Types of Ciphers
0 Methods of Encryption
0 Type of Asymmetric Systems
0 Message Integrity
0 PKI
0 Key Management
0 Link / End-to-end Encryption
0 Email standards
0 Internet security
0 Attacks
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Legal Regulation and Compliance Investigation
0 Cyber law and Cyber crime
0 Intellectual property law
0 Privacy
0 Liability and Ramifications
0 Digital Forensics and Investigations
0 Ethics
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Applications Security
0 Database Security
0 Software and applications security issues
0 Secure systems development
0 Application development and security
0 Object-oriented systems and security
0 Distributed computing and security
0 Expert systems and security
0 Web security
0 Mobile code
0 Patch management
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Operations Security
0 Role of the Operations Department
0 Administrative Management
0 Assurance Levels
0 Configuration management
0 Media Controls
0 Data Leakage
0 Network and Resource Availability
0 Mainframes
0 Email Security
0 Vulnerability testing
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Information Governance and Risk Management
0 Security Management, Administration and Governance
0 Policies, Standards, Guidelines, Procedures
0 Information Classification
0 Roles and Responsibilities
0 Risk Management and Analysis
0 Best Practices
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Security Management, Administration and
Governance
0 Information security (ISec) describes activities that relate to the
protection of information and information infrastructure assets
against the risks of loss, misuse, disclosure or damage. Information
security management (ISM) describes controls that an organization
needs to implement to ensure that it is sensibly managing these
risks.
0 The risks to these assets can be calculated by analysis of the
following issues:
0 Threats to your assets. These are unwanted events that could cause
the deliberate or accidental loss, damage or misuse of the assets
0 Vulnerabilities. How susceptible your assets are to attack
0 Impact. The magnitude of the potential loss or the seriousness of the
event.
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Security Management, Administration and
Governance
0 Standards that are available to assist organizations implement the
appropriate programs and controls to mitigate these risks are for
example BS7799/ISO 17799, Information Technology Infrastructure
Library and COBIT.
0 Information Security Governance, Information Security Governance
or ISG, is a subset discipline of Corporate Governance focused on
information Security systems and their performance and risk
management.
0 Establish and maintain a framework to provide assurance that
information security strategies are aligned with business objectives
and consistent with applicable laws and regulations
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Security Management, Administration and
Governance
0 Develop the information security strategy in support of business
strategy and direction.
0 Obtain senior management commitment and support
0 Ensure that definitions of roles and responsibilities throughout the
enterprise include information security governance activities.
0 Establish reporting and communication channels that support
information security governance activities.
0 Identify current and potential legal and regulatory issues affecting
information security and assess their impact on the enterprise.
0 Establish and maintain information security policies that support
business goals and objectives.
0 Ensure the development of procedures and guidelines that support
information security policies.
0 Develop business case for information security program
investments.
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Policies, Standards, Guidelines and Procedures
0 Policies are the top tier of formalized security documents. These
high-level documents offer a general statement about the
organization’s assets and what level of protection they should have.
0 Well-written policies should spell out who’s responsible for security,
what needs to be protected, and what is an acceptable level of risk..
0 Standards are much more specific than policies. Standards are
tactical documents because they lay out specific steps or processes
required to meet a certain requirement. As an example, a standard
might set a mandatory requirement that all email communication be
encrypted. So although it does specify a certain standard, it doesn’t
spell out how it is to be done. That is left for the procedure.
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Policies, Standards, Guidelines and Procedures
0 A baseline is a minimum level of security that a system, network, or
device must adhere to. Baselines are usually mapped to industry
standards. As an example, an organization might specify that all
computer systems comply with a minimum Trusted Computer
System Evaluation Criteria (TCSEC) C2 standard.
0 A guideline points to a statement in a policy or procedure by which
to determine a course of action. It’s a recommendation or
suggestion of how things should be done. It is meant to be flexible
so it can be customized for individual situations.
0 A procedure is the most specific of security documents. A procedure
is a detailed, in-depth, step-by-step document that details exactly
what is to be done.
0 A security model is a scheme for specifying and enforcing security
policies. Examples include: Bell and LaPadula, Biba, Access control
lists
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Information Classification
0 It is essential to classify information according to its actual value
and level of sensitivity in order to deploy the appropriate level of
security.
0
A system of classification should ideally be:
- simple to understand and to administer
- effective in order to determine the level of protection the
information is given.
- applied uniformly throughout the whole organization (note:
when in any doubt, the higher, more secure classification should
be employed).
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Information Classification
0 With the exception of information that is already in the public
domain, information should not be divulged to anyone who is not
authorized to access it or is not specifically authorized by the
information owner.
0 Violations of the Information Classification Policy should result in
disciplinary proceedings against the individual.
0 Number of information classification levels in an organization should
be a manageable number as having too many makes maintenance
and compliance difficult.
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Information Classification
0 Top Secret: Highly sensitive internal documents and data. For
example, impending mergers or acquisitions, investment strategies,
plans or designs that could seriously damage the organization if lost
or made public. Information classified as Top Secret has very
restricted distribution indeed, and must be protected at all times.
Security at this level is the highest possible.
0 Highly Confidential: Information which is considered critical to the
organization’s ongoing operations and could seriously impede or
disrupt them if made shared internally or made public. Such
information includes accounting information, business plans,
sensitive information of customers of banks (etc), patients' medical
records, and similar highly sensitive data. Such information should
not be copied or removed from the organization’s operational
control without specific authority. Security should be very high.
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Information Classification
0 Proprietary: Procedures, project plans, operational work routines,
designs and specifications that define the way in which the
organization operates. Such information is usually for proprietary
use by authorized personnel only. Security at this level is high.
0 Internal Use Only: Information not approved for general circulation
outside the organization, where its disclosure would inconvenience
the organization or management, but is unlikely to result in financial
loss or serious damage to credibility/reputation. Examples include:
internal memos, internal project reports, minutes of meetings.
Security at this level is controlled but normal.
0 Public Documents: Information in the public domain: press
statements, annual reports, etc. which have been approved for
public use or distribution. Security at this level is minimal.
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Roles and Responsibilities
0 Internal Roles
- Executive Management; Information System Security
Professionals; Owners: Data and System Owners; Custodians
- Operational Staff; Users; Legal, Compliance and Privacy
Officers; Internal Auditors; Physical Security Officers
0 External Roles
- Vendors and Supplies; Contractors; Temporary Employees;
Customers; Business Partners; Outsourced Relationships;
Outsourced Security
0 Human Resources
- Employee development and management; Hiring and
termination; Signed employee agreements; Education
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Risk Management and Analysis
0 Risk is the likelihood that something bad will happen that causes
harm to an informational asset (or the loss of the asset). A
vulnerability is a weakness that could be used to endanger or cause
harm to an informational asset. A threat is anything (man made or
act of nature) that has the potential to cause harm.
0 The likelihood that a threat will use a vulnerability to cause harm
creates a risk. When a threat does use a vulnerability to inflict harm,
it has an impact. In the context of information security, the impact is
a loss of availability, integrity, and confidentiality, and possibly other
losses (lost income, loss of life, loss of real property). It should be
pointed out that it is not possible to identify all risks, nor is it
possible to eliminate all risk. The remaining risk is called residual
risk.
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Risk Managementg and Analysis
0 A risk assessment is carried out by a team of people who have
knowledge of specific areas of the business. Membership of the
team may vary over time as different parts of the business are
assessed.
0 The assessment may use a subjective qualitative analysis based on
informed opinion (scenarios), or where reliable dollar figures and
historical information is available, the analysis may use quantitative
analysis
0 For any given risk, Executive Management can choose to accept the
risk based upon the relative low value of the asset, the relative low
frequency of occurrence, and the relative low impact on the
business. Or, leadership may choose to mitigate the risk by
selecting and implementing appropriate control measures to reduce
the risk. In some cases, the risk can be transferred to another
business by buying insurance or out-sourcing to another business.
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Risk Management and Analysis
0 Identification of assets and estimating their value. Include: people,
buildings, hardware, software, data supplies.
0 Conduct a threat assessment. Include: Acts of nature, accidents,
malicious acts originating from inside or outside the organization.
0 Conduct a vulnerability assessment, and for each vulnerability,
calculate the probability that it will be exploited. Evaluate policies,
procedures, standards, training, physical security, - - 0 Calculate the impact that each threat would have on each asset. Use
qualitative analysis or quantitative analysis.
0 Identify, select and implement appropriate controls. Provide a
proportional response. Consider productivity, cost effectiveness,
and value of the asset.
0 Evaluate the effectiveness of the control measures. Ensure the
controls provide the required cost effective protection without
discernible loss of productivity.
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Risk Management and Analysis
0 Step 1: Estimate Potential Loss
- SLE = AV ($) x EF (%)
- SLE: Single Loss Expectancy, AV: Asset Value. EF: Exposure
Factor (percentage of asset value)
0 Step 2: Conduct Threat Likelihood Analysis
- ARO Annual Rate of Occurrence
- Number of times per year that an incident is likely to occur
0 Step 3: Calculate ALE
- ALE: Annual Loss Expectancy
- ALE = SLE x ARO
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Security Best Practices
0 Job Rotation
0 Separation of Duty
0 Security Awareness training
0 Ethics Education
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Security Architecture and Design
0 Computer Architecture
0 Operating System
0 System Architecture
0 Security Architecture
0 Security Models
0 Security Models of Operation
0 System Evaluation Methods
0 Open Vs Closed Systems
0 Some security threats
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Computer Architecture Components
0 Central Processing Unit (CPU)
0 Registers
0 Memory Units
0 Input/output Processors
0 Single Processor
0 Multi-Processor
0 Multi-Core Architecture
0 Grids and Clouds
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Operating Systems
0 Memory Management
0 Process management
0 File Management
0 Capability Domains
0 Virtual Machines
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System Architecture
0 The software components that make up the system
0 Middleware
0 Database management
0 Networks
0 Applications
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Security Architecture
0 Security critical components of the system
0 Trusted Computing Base
0 Reference Monitor and Security Kernel
0 Security Perimeter
0 Security Policy
0 Least Privilege
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Trusted Computing Base
0 The trusted computing base (TCB) of a computer system is the set of
all hardware, firmware, and/or software components that are critical
to its security, in the sense that bugs or vulnerabilities occurring
inside the TCB might jeopardize the security properties of the entire
system. By contrast, parts of a computer system outside the TCB
must not be able to misbehave in a way that would leak any more
privileges than are granted to them in accordance to the security
policy.
0 The careful design and implementation of a system's trusted
computing base is paramount to its overall security. Modern
operating systems strive to reduce the size of the TCB so that an
exhaustive examination of its code base (by means of manual or
computer-assisted software audit or program verification) becomes
feasible.
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Reference Monitor and Security Kernel
0 In operating systems architecture, a reference monitor is a
tamperproof, always-invoked, and small-enough-to-be-fully-testedand-analyzed module that controls all software access to data
objects or devices (verifiable).
0 The reference monitor verifies that the request is allowed by the
access control policy.
0 For example, Windows 3.x and 9x operating systems were not built
with a reference monitor, whereas the Windows NT line, which also
includes Windows 2000 and Windows XP, was designed to contain a
reference monitor, although it is not clear that its properties
(tamperproof, etc.) have ever been independently verified, or what
level of computer security it was intended to provide.
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Security Models
0 Bell and LaPadula (BLP) Confidentiality Model
0 Biba Integrity Model (opposite to BLP)
0 Clark Wilson Integrity Model
0 Other Models
- information Flow Model
- Non Interference Model
- Graham Denning Model
- Harrison-Ruzzo-Ullman Model
- Lattice Model
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Bell and LaPadula
0 A system state is defined to be "secure" if the only permitted access modes
of subjects to objects are in accordance with a security policy. To determine
whether a specific access mode is allowed, the clearance of a subject is
compared to the classification of the object (more precisely, to the
combination of classification and set of compartments, making up the
security level) to determine if the subject is authorized for the specific access
mode. The clearance/classification scheme is expressed in terms of a lattice.
The model defines two mandatory access control (MAC) rules and one
discretionary access control (DAC) rule with three security properties:
0 The Simple Security Property - a subject at a given security level may not
read an object at a higher security level (no read-up).
0 The *-property (read "star"-property) - a subject at a given security level must
not write to any object at a lower security level (no write-down). The *property is also known as the Confinement property.
0 The Discretionary Security Property - use of an access matrix to specify the
discretionary access control.
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Biba
0 In general, preservation of data integrity has three goals:
- Prevent data modification by unauthorized parties
- Prevent unauthorized data modification by authorized parties
- Maintain internal and external consistency (i.e. data reflects the real
world)
0 Biba security model is directed toward data integrity (rather than
confidentiality) and is characterized by the phrase: "no read down, no write
up". This is in contrast to the Bell-LaPadula model which is characterized by
the phrase "no write down, no read up".
0 The Biba model defines a set of security rules similar to the Bell-LaPadula
model. These rules are the reverse of the Bell-LaPadula rules:
0 The Simple Integrity Axiom states that a subject at a given level of integrity
must not read an object at a lower integrity level (no read down).
0 The * (star) Integrity Axiom states that a subject at a given level of integrity
must not write to any object at a higher level of integrity (no write up).
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Clark Wilson Model
0 The Clark-Wilson integrity model provides a foundation for
specifying and analyzing an integrity policy for a computing system.
0 The model is primarily concerned with formalizing the notion of
information integrity.
0 Information integrity is maintained by preventing corruption of data
items in a system due to either error or malicious intent.
0 An integrity policy describes how the data items in the system
should be kept valid from one state of the system to the next and
specifies the capabilities of various principals in the system.
0 The model defines enforcement rules and certification rules.
0 The model’s enforcement and certification rules define data items
and processes that provide the basis for an integrity policy. The core
of the model is based on the notion of a transaction.
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Clark Wilson Model
0 A well-formed transaction is a series of operations that transition a system
from one consistent state to another consistent state.
0 In this model the integrity policy addresses the integrity of the transactions.
0 The principle of separation of duty requires that the certifier of a transaction
and the implementer be different entities.
0 The model contains a number of basic constructs that represent both data
items and processes that operate on those data items. The key data type in
the Clark-Wilson model is a Constrained Data Item (CDI). An Integrity
Verification Procedure (IVP) ensures that all CDIs in the system are valid at a
certain state. Transactions that enforce the integrity policy are represented
by Transformation Procedures (TPs). A TP takes as input a CDI or
Unconstrained Data Item (UDI) and produces a CDI. A TP must transition the
system from one valid state to another valid state. UDIs represent system
input (such as that provided by a user or adversary). A TP must guarantee
(via certification) that it transforms all possible values of a UDI to a “safe”
CDI
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Clark Wilson Model
0 At the heart of the model is the notion of a relationship between an
authenticated principal (i.e., user) and a set of programs (i.e., TPs) that
operate on a set of data items (e.g., UDIs and CDIs). The components of such
a relation, taken together, are referred to as a Clark-Wilson triple. The model
must also ensure that different entities are responsible for manipulating the
relationships between principals, transactions, and data items. As a short
example, a user capable of certifying or creating a relation should not be able
to execute the programs specified in that relation.
0 The model consists of two sets of rules: Certification Rules (C) and
Enforcement Rules (E). The nine rules ensure the external and internal
integrity of the data items. To paraphrase these:
0 C1—When an IVP is executed, it must ensure the CDIs are valid. C2—For
some associated set of CDIs, a TP must transform those CDIs from one valid
state to another. Since we must make sure that these TPs are certified to
operate on a particular CDI, we must have E1 and E2.
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Clark Wilson Model
0
E1—System must maintain a list of certified relations and ensure only TPs certified to
run on a CDI change that CDI. E2—System must associate a user with each TP and set of
CDIs. The TP may access the CDI on behalf of the user if it is “legal.” This requires
keeping track of triples (user, TP, {CDIs}) called “allowed relations.”
0
C3—Allowed relations must meet the requirements of “separation of duty.” We need
authentication to keep track of this.
0
E3—System must authenticate every user attempting a TP. Note that this is per TP
request, not per login. For security purposes, a log should be kept.
0
C4—All TPs must append to a log enough information to reconstruct the operation.
When information enters the system it need not be trusted or constrained (i.e. can be a
UDI). We must deal with this appropriately.
0
C5—Any TP that takes a UDI as input may only perform valid transactions for all possible
values of the UDI. The TP will either accept (convert to CDI) or reject the UDI. Finally, to
prevent people from gaining access by changing qualifications of a TP:
0
E4—Only the certifier of a TP may change the list of entities associated with that TP
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Security Modes of Operation
0 Dedicated
0 Systems High
0 Compartmented
0 Multilevel
0 Trust and Assurance
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Secure System Evaluation: TCSEC
0 Trusted Computer System Evaluation Criteria (TCSEC) is a United
States Government Department of Defense (DoD) standard that sets
basic requirements for assessing the effectiveness of computer
security controls built into a computer system. The TCSEC was used
to evaluate, classify and select computer systems being considered
for the processing, storage and retrieval of sensitive or classified
information.
0 The TCSEC, frequently referred to as the Orange Book, is the
centerpiece of the DoD Rainbow Series publications. Initially issued
in 1983 by the National Computer Security Center (NCSC), an arm of
the National Security Agency, and then updated in 1985,.
0
TCSEC was replaced by the Common Criteria international standard
originally published in 2005.
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Secure System Evaluation: TCSEC
0 Policy: The security policy must be explicit, well-defined and
enforced by the computer system. There are two basic security
policies:
0 Mandatory Security Policy - Enforces access control rules based
directly on an individual's clearance, authorization for the
information and the confidentiality level of the information being
sought. Other indirect factors are physical and environmental. This
policy must also accurately reflect the laws, general policies and
other relevant guidance from which the rules are derived.
- Marking - Systems designed to enforce a mandatory security
policy must store and preserve the integrity of access control
labels and retain the labels if the object is exported.
0 Discretionary Security Policy - Enforces a consistent set of rules for
controlling and limiting access based on identified individuals who
have been determined to have a need-to-know for the information.
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Secure System Evaluation: TCSEC
0 Accountability: Individual accountability regardless of policy must be
enforced. A secure means must exist to ensure the access of an authorized
and competent agent which can then evaluate the accountability information
within a reasonable amount of time and without undue difficulty. There are
three requirements under the accountability objective:
0 Identification - The process used to recognize an individual user.
0 Authentication - The verification of an individual user's authorization to
specific categories of information.
0 Auditing - Audit information must be selectively kept and protected so that
actions affecting security can be traced to the authenticated individual.
0 The TCSEC defines four divisions: D, C, B and A where division A has the
highest security. Each division represents a significant difference in the trust
an individual or organization can place on the evaluated system. Additionally
divisions C, B and A are broken into a series of hierarchical subdivisions
called classes: C1, C2, B1, B2, B3 and A1.
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Secure System Evaluation: TCSEC
0 Assurance: The computer system must contain
hardware/software mechanisms that can be independently
evaluated to provide sufficient assurance that the system
enforces the above requirements. By extension, assurance
must include a guarantee that the trusted portion of the
system works only as intended. To accomplish these
objectives, two types of assurance are needed with their
respective elements:
0 Assurance Mechanisms : Operational Assurance: System
Architecture, System Integrity, Covert Channel Analysis,
Trusted Facility Management and Trusted Recovery
0 Life-cycle Assurance : Security Testing, Design Specification
and Verification, Configuration Management and Trusted
System Distribution
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Secure System Evaluation: ITSEC
0 The Information Technology Security Evaluation Criteria
(ITSEC) is a structured set of criteria for evaluating computer
security within products and systems. The ITSEC was first
published in May 1990 in France, Germany, the Netherlands,
and the United Kingdom based on existing work in their
respective countries. Following extensive international
review, Version 1.2 was subsequently published in June 1991
by the Commission of the European Communities for
operational use within evaluation and certification schemes.
0 Levels E1 – E6
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Secure System Evaluation: Common Criteria
0 The Common Criteria for Information Technology Security
Evaluation (abbreviated as Common Criteria or CC) is an
international standard (ISO/IEC 15408) for computer security
certification.
0 Common Criteria is a framework in which computer system users
can specify their security functional and assurance requirements,
vendors can then implement and/or make claims about the security
attributes of their products, and testing laboratories can evaluate the
products to determine if they actually meet the claims. In other
words, Common Criteria provides assurance that the process of
specification, implementation and evaluation of a computer security
product has been conducted in a rigorous and standard manner.
0 Levels: EAL 1 – EAL 7 (Evaluation Assurance Levels)
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Certification and Accreditation
0 Certification and Accreditation (C&A) is a process for implementing
information security. It is a systematic procedure for evaluating,
describing, testing and authorizing systems prior to or after a
system is in operation.
0 Certification is a comprehensive assessment of the management,
operational, and technical security controls in an information
system, made in support of security accreditation, to determine the
extent to which the controls are implemented correctly, operating as
intended, and producing the desired outcome with respect to
meeting the security requirements for the system.
0 Accreditation is the official management decision given by a senior
agency official to authorize operation of an information system and
to explicitly accept the risk to agency operations (including mission,
functions, image, or reputation), agency assets, or individuals,
based on the implementation of an agreed-upon set of security
controls.
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Access Control
0 Access Control Overview
0 Identification, Authentication, Authorization, Accountability
0 Single Sign-on and Kerberos
0 Access Control Models
0 Access Control Techniques and Technologies
0 Access Control Administration
0 Access Control Monitoring: Intrusion Detection
0 Threats to Access Control
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Access Control Overview
0 Access control is a system which enables an authority to control
access to areas and resources in a given physical facility or
computer-based information system.
0 In computer security, access control includes authentication,
authorization and audit. It also includes measures such as physical
devices, including biometric scans and metal locks, hidden paths,
digital signatures, encryption, social barriers, and monitoring by
humans and automated systems.
0 In any access control model, the entities that can perform actions in
the system are called subjects, and the entities representing
resources to which access may need to be controlled are called
objects (see also Access Control Matrix). Subjects and objects
should both be considered as software entities and as human users
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Access Control
0 Access control models used by current systems tend to fall into one
of two classes: those based on capabilities and those based on
access control lists (ACLs).
0 In a capability-based model, holding an unforgeable reference or
capability to an object provides access to the object
0 Access is conveyed to another party by transmitting such a
capability over a secure channel.
0
In an ACL-based model, a subject's access to an object depends on
whether its identity is on a list associated with the object
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Identification, Authentication, Authorization
0 Access control systems provide the essential services of
identification and authentication (I&A), authorization, and
accountability where:
0 identification and authentication determine who can log on to a
system, and the association of users with the software subjects that
they are able to control as a result of logging in;
0 authorization determines what a subject can do;
0 accountability identifies what a subject (or all subjects associated
with a user) did.
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Single Sign-On
0 Single sign-on (SSO) is a property of access control of multiple,
related, but independent software systems. With this property a user
logs in once and gains access to all systems without being
prompted to log in again at each of them. Single sign-off is the
reverse property whereby a single action of signing out terminates
access to multiple software systems.
0 As different applications and resources support different
authentication mechanisms, single sign-on has to internally
translate to and store different credentials compared to what is used
for initial authentication.
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Single Sign-on Kerberos
0 Kerberos is a computer network authentication protocol, which
allows nodes communicating over a non-secure network to prove
their identity to one another in a secure manner. It is also a suite of
free software published by MIT that implements this protocol. Its
designers aimed primarily at a client–server model, and it provides
mutual authentication — both the user and the server verify each
other's identity. Kerberos protocol messages are protected against
eavesdropping and replay attacks.
0 Kerberos builds on symmetric key cryptography and requires a
trusted third party, and optionally may use public-key cryptography
by utilizing asymmetric key cryptography during certain phases of
authentication
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Kerberos
0 Kerberos uses as its basis the symmetric Needham-Schroeder
protocol. It makes use of a trusted third party, termed a key
distribution center (KDC), which consists of two logically separate
parts: an Authentication Server (AS) and a Ticket Granting Server
(TGS). Kerberos works on the basis of "tickets" which serve to prove
the identity of users.
0 The KDC maintains a database of secret keys; each entity on the
network — whether a client or a server — shares a secret key known
only to itself and to the KDC. Knowledge of this key serves to prove
an entity's identity. For communication between two entities, the
KDC generates a session key which they can use to secure their
interactions.
0 The security of the protocol relies heavily on participants
maintaining loosely synchronized time and on short-lived assertions
of authenticity called Kerberos tickets.
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Kerberos
0 The client authenticates itself to the Authentication Server and
receives a ticket. (All tickets are time-stamped.)
0 It then contacts the Ticket Granting Server, and using the ticket it
demonstrates its identity and asks for a service.
0
If the client is eligible for the service, then the Ticket Granting
Server sends another ticket to the client.
0 The client then contacts the Service Server, and using this ticket it
proves that it has been approved to receive the service.
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Access Control Techniques
0 Role based access control
0 Constrained user interfaces
0 Access control Matrix
0 Content dependent access control
0 Content dependent access control
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Access Control
0 Access control techniques: Access control techniques are sometimes
categorized as either discretionary or non-discretionary. The three most
widely recognized models are Discretionary Access Control (DAC),
Mandatory Access Control (MAC), and Role Based Access Control (RBAC).
MAC and RBAC are both non-discretionary.
0 Attribute-based Access Control: In attribute-based access control, access is
granted not based on the rights of the subject associated with a user after
authentication, but based on attributes of the user. The user has to prove so
called claims about his attributes to the access control engine. An attributebased access control policy specifies which claims need to satisfied in order
to grant access to an object. For instance the claim could be "older than 18" .
Any user that can prove this claim is granted access. Users can be
anonymous as authentication and identification are not strictly required. One
does however require means for proving claims anonymously. This can for
instance be achieved using Anonymous credentials.
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Access Control
0 Discretionary access control: (DAC) is an access policy determined
by the owner of an object. The owner decides who is allowed to
access the object and what privileges they have.
0 Two important concepts in DAC are
0 File and data ownership: Every object in the system has an owner. In
most DAC systems, each object's initial owner is the subject that
caused it to be created. The access policy for an object is
determined by its owner.
0 Access rights and permissions: These are the controls that an owner
can assign to other subjects for specific resources.
0 Access controls may be discretionary in ACL-based or capability-
based access control systems. (In capability-based systems, there is
usually no explicit concept of 'owner', but the creator of an object
has a similar degree of control over its access policy.)
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Access Control
0 Mandatory access control: (MAC) is an access policy determined by the
system, not the owner. MAC is used in multilevel systems that process highly
sensitive data, such as classified government and military information. A
multilevel system is a single computer system that handles multiple
classification levels between subjects and objects.
0 Sensitivity labels: In a MAC-based system, all subjects and objects must
have labels assigned to them. A subject's sensitivity label specifies its level
of trust. An object's sensitivity label specifies the level of trust required for
access. In order to access a given object, the subject must have a sensitivity
level equal to or higher than the requested object.
0 Data import and export: Controlling the import of information from other
systems and export to other systems (including printers) is a critical function
of MAC-based systems, which must ensure that sensitivity labels are
properly maintained and implemented so that sensitive information is
appropriately protected at all times.
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What is Biometrics?
0 Biometrics are automated methods of recognizing a person based
on a physiological or behavioral characteristic
0 Features measured: Face, Fingerprints, Hand geometry, handwriting,
Iris, Retinal, Vein and Voice
0 Identification and personal certification solutions for highly secure
applications
0 Numerous applications: medical, financial, child care, computer
access etc.
0 Biometrics replaces Traditional Authentication Methods
0 Provides better security
0 More convenient
0 Better accountability
0 Applications on Fraud detection and Fraud deterrence
0 Dual purpose: Cyber Security and National Security
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What is the Process?
0 Three-steps: Capture-Process-Verification
0 Capture: A raw biometric is captured by a sensing device
such as fingerprint scanner or video camera
0 Process: The distinguishing characteristics are extracted
from the raw biometrics sample and converted into a
processed biometric identifier record
- Called biometric sample or template
0 Verification and Identification
- Matching the enrolled biometric sample against a single
record; is the person really what he claims to be?
- Matching a biometric sample against a database of
identifiers
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Security Vulnerabilities
0 Type 1 attack: present fake biometric such a synthetic
0
0
0
0
0
biometric
Type 2 attack: Submit a previously intercepted biometric data:
replay
Type 3 attack: Compromising the feature extractor module to
give results desired by attacker
Type 4 attack: Replace the genuine feature values produced
by the system by fake values desired by attacker
Type 5 attack: Produce a high number of matching results
Type 6 attack: Attack the template database: add templates,
modify templates etc.
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Access Conrol Administration
0 Access Contol Administration will work out how the organiztion will
adninistrw access control: Centralzied or Distributed.
0 Terminal Access Controller Access-Control System (TACACS) is a remote
authentication protocol that is used to communicate with an authentication
server commonly used in UNIX networks.
0 TACACS allows a client to accept a username and password and send a
query to a TACACS authentication server, sometimes called a TACACS
daemon or XTACACS. This server was normally a program running on a host.
The host would determine whether to accept or deny the request and send a
response back. The TIP (routing node accepting dial-up line connections,
which the user would normally want to log in into) would then allow access
or not, based upon the response.
0 TACACS+ and RADIUS have generally replaced TACACS. TACACS+ is an
entirely new protocol and not compatible with TACACS or XTACACS.
TACACS+ uses the Transmission Control Protocol (TCP) and RADIUS uses
the User Datagram Protocol (UDP).
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Intrusion Detection System
0 An IDS is a device (or application) that monitors network and/or
system activities for malicious activities or policy violations and
produces reports to a Management Station.[
0 Intrusion prevention is the process of performing intrusion detection
and attempting to stop detected possible incidents.
0 Intrusion detection and prevention systems (IDPS) are primarily
focused on identifying possible incidents, logging information about
them, attempting to stop them, and reporting them to security
administrators.
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Threats to Access Control
0 Dictionary Attack
0 Brute Force Attack
0 Spoofing at Logon
0 Phishing
0 Identity Theft
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Crypography
0 Definition of Cryptography
0 Important concepts
- Symmetric and Asymmetric, Hash, Digital Signature etc.
0 Steganography and Digital watermarking
0 Algorithms
0 Attacks
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Definitions
0 Cryptography
- Mathematical manipulation of information that prevents the
information being disclosed or altered
0 Cryptanalysis
- Defeating the protected mechanisms of cryptography
0 Cryptology
- Study of Cryptography and Cryptanalysis
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Goals of Cryptography
0 Confidentiality
0 Integrity
0 Authenticity
0 Non-repudiation
0 Access Control
0 Make compromise difficult
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Process
0 Input (also called Plaintext or Clear Text)
0 Cryptosystem (device that performs encryption/decryption)
0 Cryptographic Algorithms (Mathematical functions)
0 Output (Cipher text or Cryptogram)
0 Key (Crypto variable)
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Key Clustering
0 In cryptography, key clustering is said to occur when two different
keys generate the same ciphertextfrom the same plaintext, using the
same cipher algorithm. A good cipher algorithm, using different keys
on the same plaintext, should generate a different ciphertext,
irrespective of the key length.
0 If an 'attacker' tries to break a cipher by brute-force (trying all
possible keys until it finds the correct key) then key clustering will
result in an easier attack on a particular cipher text. If there are N
possible keys with out any key clustering then the attacker will on
average need to try N/2 keys to decrypt it and a worst case of trying
all N keys. If there are two keys that are clustered then the average
number of keys to try is reduced to N/4 (worst case is N-1 keys). If
three keys cluster than average attempt is only N/6 attempts.
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Symmetric Key Cryptography
0 Symmetric-key algorithms are a class of algorithms for cryptography
that use trivially related, often identical, cryptographic keys for both
decryption and encryption.
0 The encryption key is trivially related to the decryption key, in that
they may be identical or there is a simple transformation to go
between the two keys. The keys, in practice, represent a shared
secret between two or more parties that can be used to maintain a
private information link.
0 The disadvantage of symmetric cryptography is that it presumes two
parties have agreed on a key and been able to exchange that key in a
secure manner prior to communication. This is a significant
challenge. Symmetric algorithms are usually mixed with public key
algorithms to obtain a blend of security and speed.
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Public Key Cryptography
0 Public-key cryptography is a cryptographic approach which involves
the use of asymmetric key algorithms instead of or in addition to
symmetric key algorithms.
0 Unlike symmetric key algorithms, it does not require a secure initial
exchange of one or more secret keys to both sender and receiver.
0 The asymmetric key algorithms are used to create a mathematically
related key pair: a secret private key and a published public key. Use
of these keys allows protection of the authenticity of a message by
creating a digital signature of a message using the private key,
which can be verified using the public key.
0 It also allows protection of the confidentiality and integrity of a
message, by public key encryption, encrypting the message using
the public key, which can only be decrypted using the private key.
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Public Key Cryptography
0 Public key cryptography is a fundamental and widely used
technology around the world. It is the approach which is employed
by many cryptographic algorithms and cryptosystems. It underlies
such Internet standards as Transport Layer Security (TLS)
(successor to SSL), PGP, and GPG.
0 Uses asymmetric key algorithms, where the key used to encrypt a
message is not the same as the key used to decrypt it. Each user
has a pair of cryptographic keys—a public key and a private key. The
private key is kept secret, whilst the public key may be widely
distributed. Messages are encrypted with the recipient's public key
and can only be decrypted with the corresponding private key. The
keys are related mathematically, but the private key cannot be
feasibly derived from the public key.
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Initialization Vector
0 In cryptography, an initialization vector (IV) is a block of bits that is
required to allow a stream cipher or a block cipher to be executed in
any of several modes of operation to produce a unique stream
independent from other streams produced by the same encryption
key, without having to go through a (usually lengthy) re-keying
process.
0 The size of the IV depends on the encryption algorithm and on the
cryptographic protocol in use and is normally as large as the block
size of the cipher or as large as the encryption key.
0 The IV must be known to the recipient of the encrypted information
to be able to decrypt it.
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Initialization Vector
0 This can be ensured in a number of ways: by transmitting the IV
along with the cipher text, by agreeing on it beforehand during the
key exchange or the handshake, by calculating it (usually
incrementally), or by measuring such parameters as current time
(used in hardware authentication tokens such as RSA SecurID) IDs
such as sender's and/or recipient's address or ID, file ID, the packet,
sector or cluster number, etc.
0 A number of variables can be combined or hashed together,
depending on the protocol. If the IV is chosen at random, the
cryptographer must take into consideration the probability of
collisions, and if an incremental IV is used as a nonce, the
algorithm's resistance to related-IV attacks must also be considered.
0 Nonce – number used once
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Block Cipher
0 In cryptography, a block cipher is a symmetric key cipher operating
on fixed-length groups of bits, called blocks, with an unvarying
transformation. A block cipher encryption algorithm might take (for
example) a 128-bit block of plaintext as input, and output a
corresponding 128-bit block of ciphertext. The exact transformation
is controlled using a second input — the secret key. Decryption is
similar: the decryption algorithm takes, in this example, a 128-bit
block of ciphertext together with the secret key, and yields the
original 128-bit block of plaintext.
0 To encrypt messages longer than the block size (128 bits in the
above example), a mode of operation is used.
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Block Cipher
0 Block ciphers can be contrasted with stream ciphers; a stream
cipher operates on individual digits one at a time, and the
transformation varies during the encryption.
0 The distinction between the two types is not always clear-cut: a
block cipher, when used in certain modes of operation, acts
effectively as a stream cipher.
0 An early and highly influential block cipher design was the Data
Encryption Standard (DES), developed at IBM and published as a
standard in 1977. A successor to DES, the Advanced Encryption
Standard (AES), was adopted in 2001.
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Stream Cipher
0 In cryptography, a stream cipher is a symmetric key cipher where
plaintext bits are combined with a pseudorandom cipher bit stream (,
(keystreams) typically by an exclusive-or (XOR) operation.
0
0
In a stream cipher the plaintext digits are encrypted one at a time,
and the transformation of successive digits varies during the
encryption. An alternative name is a state cipher, as the encryption
of each digit is dependent on the current state.
In practice, the digits are typically single bits or bytes.
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Stream Cipher
0 Stream ciphers represent a different approach to symmetric
encryption from block ciphers.
0 Block ciphers operate on large blocks of digits with a fixed,
unvarying transformation. This distinction is not always clear-cut: in
some modes of operation, a block cipher primitive is used in such a
way that it acts effectively as a stream cipher.
0 Stream ciphers typically execute at a higher speed than block
ciphers and have lower hardware complexity. However, stream
ciphers can be susceptible to serious security problems if used
incorrectly: see stream cipher attacks — in particular, the same
starting state must never be used twice.
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Digital Signature
0 A digital signature or digital signature scheme is a mathematical
scheme for demonstrating the authenticity of a digital message or
document. A valid digital signature gives a recipient reason to
believe that the message was created by a known sender, and that it
was not altered in transit. Digital signatures are commonly used for
software distribution, financial transactions, and in other cases
where it is important to detect forgery and tampering.
0 Digital signatures are often used to implement electronic signatures,
a broader term that refers to any electronic data that carries the
intent of a signature, but not all electronic signatures use digital
signatures.[In some countries, including the United States, India, and
members of the European Union, electronic signatures have legal
significance. However, laws concerning electronic signatures do not
always make clear whether they are digital cryptographic signatures
in the sense used here, leaving the legal definition, and so their
importance, somewhat confused.
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Digital Signature
0 Digital signatures employ a type of asymmetric cryptography. For messages
sent through an insecure channel, a properly implemented digital signature
gives the receiver reason to believe the message was sent by the claimed
sender. Digital signatures are equivalent to traditional handwritten signatures
in many respects; properly implemented digital signatures are more difficult
to forge than the handwritten type. Digital signature schemes in the sense
used here are cryptographically based, and must be implemented properly to
be effective.
0 Digital signatures can also provide non-repudiation, meaning that the signer
cannot successfully claim they did not sign a message, while also claiming
their private key remains secret; further, some non-repudiation schemes
offer a time stamp for the digital signature, so that even if the private key is
exposed, the signature is valid nonetheless. Digitally signed messages may
be anything representable as a bitstring: examples include electronic mail,
contracts, or a message sent via some other cryptographic protocol.
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Work Factor
0 Work Factor is defined as the amount of effort (usually measured in
units of time) needed to break a cryptosystem.
0 The Work Factor of a cryptosystem is related to its key-length and
the working mechanism used (encryption and decryption
algorithms). For example, if the brute force attack method is used to
break the system (trying all possible combinations of the key), then
the work factor is directly proportional to the length of the key. For
every addition of one bit to the key length, the time needed (work
factor) is doubled.
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Hash Function
0 A hash function is any well-defined procedure or mathematical
function that converts a large, possibly variable-sized amount of
data into a small datum, usually a single integer that may serve as an
index to an array. The values returned by a hash function are called
hash values, hash codes, hash sums, checksums or simply hashes.
0 A hash function may map two or more keys to the same hash value.
In many applications, it is desirable to minimize the occurrence of
such collisions, which means that the hash function must map the
keys to the hash values as evenly as possible.
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Checksum
0 A checksum or hash sum is a fixed-size datum computed from an
arbitrary block of digital data for the purpose of detecting accidental
errors that may have been introduced during its transmission or
storage.
0 The integrity of the data can be checked at any later time by
recomputing the checksum and comparing it with the stored one. If
the checksums do not match, the data was almost certainly altered
(either intentionally or unintentionally).
0 The procedure that yields the checksum from the data is called a
checksum function or checksum algorithm. A good checksum
algorithm will yield a different result with high probability when the
data is accidentally corrupted; if the checksums match, the data is
very likely to be free of accidental errors.
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Substitution Ciphers
0 In cryptography, a substitution cipher is a method of encryption by
which units of plaintext are replaced with cipher text according to a
regular system; the "units" may be single letters (the most common),
pairs of letters, triplets of letters, mixtures of the above, and so forth.
The receiver deciphers the text by performing an inverse
substitution.
0 Substitution ciphers can be compared with transposition ciphers. In
a transposition cipher, the units of the plaintext are rearranged in a
different and usually quite complex order, but the units themselves
are left unchanged. By contrast, in a substitution cipher, the units of
the plaintext are retained in the same sequence in the ciphertext, but
the units themselves are altered.
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Substitution Ciphers
0 There are a number of different types of substitution cipher. If the
cipher operates on single letters, it is termed a simple substitution
cipher; a cipher that operates on larger groups of letters is termed
polygraphic. A monoalphabetic cipher uses fixed substitution over
the entire message, whereas a polyalphabetic cipher uses a number
of substitutions at different times in the message, where a unit from
the plaintext is mapped to one of several possibilities in the
ciphertext and vice-versa.
0 Substitution over a single letter—simple substitution—can be
demonstrated by writing out the alphabet in some order to represent
the substitution. This is termed a substitution alphabet. The cipher
alphabet may be shifted or reversed (e.g., Caesar ) or scrambled in a
more complex fashion, in which case it is called a mixed alphabet.
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Message Authentication Codes
0 In cryptography, a message authentication code (often MAC) is a
short piece of information used to authenticate a message.
0 A MAC algorithm, sometimes called a keyed (cryptographic) hash
function, accepts as input a secret key and an arbitrary-length
message to be authenticated, and outputs a MAC (sometimes known
as a tag). The MAC value protects both a message's data integrity as
well as its authenticity, by allowing verifiers (who also possess the
secret key) to detect any changes to the message content.
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Key Management
0 Key management is the provisions made in a cryptography system
design that are related to generation, exchange, storage,
safeguarding, use, vetting, and replacement of keys. It includes
cryptographic protocol design, key servers, user procedures, and
other relevant protocols.
0 Key management concerns keys at the user level, either between
users or systems. This is in contrast to key scheduling; key
scheduling typically refers to the internal handling of key material
within the operation of a cipher.
0 Successful key management is critical to the security of a
cryptosystem. In practice it is arguably the most difficult aspect of
cryptography because it involves system policy, user training,
organizational and departmental interactions, and coordination
between all of these elements.
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Certificate Authority
0 In cryptography, a certificate authority or certification authority (CA)
is an entity that issues digital certificates for use by other parties. It
is an example of a trusted third party. CAs are characteristic of many
public key infrastructure (PKI) schemes.
0 Commercial CAs charge to issue certificates that will automatically
be trusted by most web browsers (Mozilla maintains a list of at least
36 trusted root CAs, though multiple commercial CAs or their
resellers may share the same trusted root ).
0 The number of web browsers and other devices and applications
that trust a particular certificate authority is referred to as ubiquity.
0 Aside from commercial CAs, some providers issue digital
certificates to the public at no cost. Large institutions or government
entities may have their own CAs.
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Certificate Authority
0 Certificate-based encryption is a system in which a certificate
authority uses ID-based cryptography to produce a certificate. This
system gives the users both implicit and explicit certification, the
certificate can be used as a conventional certificate (for signatures,
etc.), but also implicitly for the purpose of encryption.
0 A user Alice can doubly encrypt a message using another user's
(Bob) public key and his (Bob's) identity.
0 This means that the user (Bob) cannot decrypt it without a currently
valid certificate and also that the certificate authority cannot decrypt
the message as they don't have the user's private key (i.e., there is
no implicit escrow as with ID-based cryptography, as the double
encryption means they cannot decrypt it solely with the information
they have).
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Public Key Infrastructure
0 Public Key Infrastructure (PKI) is a set of hardware, software, people,
policies, and procedures needed to create, manage, distribute, use,
store, and revoke digital certificates]. In cryptography, a PKI is an
arrangement that binds public keys with respective user identities by
means of a certificate authority (CA). The user identity must be
unique within each CA domain. The binding is established through
the registration and issuance process, which, depending on the level
of assurance the binding has, may be carried out by software at a
CA, or under human supervision. The PKI role that assures this
binding is called the Registration Authority (RA) . For each user, the
user identity, the public key, their binding, validity conditions and
other attributes are made unforgeable in public key certificates
issued by the CA.
0 The term trusted third party (TTP) may also be used for certificate
authority (CA). The term PKI is sometimes erroneously used to
denote public key algorithms, which do not require the use of a CA
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Web of Trust
0 An alternative approach to the problem of public authentication of
public key information is the web of trust scheme, which uses selfsigned certificates and third party attestations of those certificates.
The singular term Web of Trust does not imply the existence of a
single web of trust, or common point of trust, but rather any number
of potentially disjoint "webs of trust". Examples of implementations
of this approach are PGP (Pretty Good Privacy)
0 Because PGP and implementations allow the use of e-mail digital
signatures for self-publication of public key information, it is
relatively easy to implement one's own Web of Trust. One of the
benefits of the Web of Trust, such as in PGP, is that it can
interoperate with a PKI CA fully-trusted by all parties in a domain
(such as an internal CA in a company) that is willing to guarantee
certificates, as a trusted introducer.
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Steganography
0 Steganography is the art and science of writing hidden messages in
such a way that no one, apart from the sender and intended
recipient, suspects the existence of the message, a form of security
through obscurity.
0 Generally, messages will appear to be something else: images,
articles, shopping lists, or some other covertext and, classically, the
hidden message may be in invisible ink between the visible lines of a
private letter.
0 The advantage of steganography, over cryptography alone, is that
messages do not attract attention to themselves.
0 Cryptography protects the contents of a message, steganography
can be said to protect both messages and communicating parties.
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Steganography
0 Steganography includes the concealment of information within
computer files.
0 In digital steganography, electronic communications may include
steganographic coding inside of a transport layer, such as a
document file, image file, program or protocol.
0 Media files are ideal for steganographic transmission because of
their large size.
0 As a simple example, a sender might start with an innocuous image
file and adjust the color of every 100th pixel to correspond to a letter
in the alphabet, a change so subtle that someone not specifically
looking for it is unlikely to notice it.
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Digital Watermarking
0 Digital watermarking is the process of embedding information into a
digital signal in a way that is difficult to remove. The signal may be
audio, pictures or video, for example. If the signal is copied, then the
information is also carried in the copy. A signal may carry several
different watermarks at the same time.
0 In visible watermarking, the information is visible in the picture or
video. Typically, the information is text or a logo which identifies the
owner of the media. The image on the right has a visible watermark.
When a television broadcaster adds its logo to the corner of
transmitted video, this is also a visible watermark.
0 In invisible watermarking, information is added as digital data to
audio, picture or video, but it cannot be perceived as such (although
it may be possible to detect that some amount of information is
hidden).
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Digital Watermarking
0 The watermark may be intended for widespread use and is thus
made easy to retrieve or it may be a form of Steganography, where a
party communicates a secret message embedded in the digital
signal. In either case, as in visible watermarking, the objective is to
attach ownership or other descriptive information to the signal in a
way that is difficult to remove. It is also possible to use hidden
embedded information as a means of covert communication
between individuals.
0 One application of watermarking is in copyright protection systems,
which are intended to prevent or deter unauthorized copying of
digital media. In this use a copy device retrieves the watermark from
the signal before making a copy; the device makes a decision to
copy or not depending on the contents of the watermark. Another
application is in source tracing. A watermark is embedded into a
digital signal at each point of distribution. If a copy of the work is
found later, then the watermark can be retrieved from the copy and
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Algorithms
0 Block Modes
- Electronic Code Block
- Cipher Block Chaining
0 Stream Modes
- Cipher Feed Back
- Output Feed Back
- Counter
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Attacks
0 Brute Force
0 Birthday
0 Dictionary
0 Known Plaintext
0 Chosen Plaintext
0 Cipher text Only
0 Chosen Cipher text
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Network Security
0 Introduction to Network Security
0 Types of Secure Network Systems
0 Secure Network Protocols
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What is Network Security
0 Network security consists of the provisions made in an underlying
computer network infrastructure, policies adopted by the network
administrator to protect the network and the network-accessible
resources from unauthorized access, and consistent and continuous
monitoring and measurement of its effectiveness
0 The terms network security and information security are often used
interchangeably. Network security is generally taken as providing
protection at the boundaries of an organization by keeping out
intruders (hackers).
0
Information security, however, explicitly focuses on protecting data
resources from malware attack or simple mistakes by people within
an organization by use of data loss prevention (DLP) techniques.
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What is Network Security
0 Network security starts from authenticating the user, commonly with
a username and a password.
0 Once authenticated, a firewall enforces access policies such as what
services are allowed to be accessed by the network users.[
0 Though effective to prevent unauthorized access, this component
may fail to check potentially harmful content such as computer
worms or Trojans being transmitted over the network.
0 Anti-virus software or an intrusion prevention system (IPS) help
detect and inhibit the action of such malware. An anomaly-based
intrusion detection system may also monitor the network and traffic
for unexpected (i.e. suspicious) content or behavior and other
anomalies to protect resources, e.g. from denial of service attacks or
an employee accessing files at strange times. Individual events
occurring on the network may be logged for audit purposes and for
later high level analysis.
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What is Network Security
0 Communication between two hosts using a network could be
encrypted to maintain privacy.
0 Honeypots essentially decoy network-accessible resources, could
be deployed in a network as surveillance and early-warning tools.
Techniques used by the attackers that attempt to compromise these
decoy resources are studied during and after an attack to keep an
eye on new exploitation techniques. Such analysis could be used to
further tighten security of the actual network being protected by the
honeypot.
0 A Botnet is a collection of software agents, or robots, that run
autonomously and automatically. The term is most commonly
associated with malicious software, but it can also refer to a network
of computers using distributed computing software.
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Network Forensic
0 Network forensics is essentially about monitoring network
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traffic and determining if there is an attack and if so,
determine the nature of the attack
Key tasks include traffic capture, analysis and visualization
Many tools are now available
Works together with IDs, Firewalls and Honeynets
Expert systems solutions show promise
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What is Network Forensics?
0 Network forensics is the capture, recording, and analysis of
network events in order to discover the source of security
attacks or other problem incidents.
0 Network forensics systems can be one of two kinds:
- "Catch-it-as-you-can" systems, in which all packets
passing through a certain traffic point are captured and
written to storage with analysis being done subsequently
in batch mode. This approach requires large amounts of
storage, usually involving a RAID system.
- "Stop, look and listen" systems, in which each packet is
analyzed in a rudimentary way in memory and only certain
information saved for future analysis. This approach
requires less storage but may require a faster processor
to keep up with incoming traffic.
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Network Forensics Analysis Tools (NFAT):
Relationships between IDS, Firewalls and NFAT
0 IDS attempts to detect activity that violates an organization’s
security policy by implementing a set of rules describing
preconfigures patterns of interest
0 Firewall allows or disallows traffic to or from specific
networks, machine addresses and port numbers
0 NFAT synergizes with IDSs and Firewalls.
- Preserves long term record of network traffic
- Allows quick analysis of trouble spots identified by IDSs
and Firewalls
0 NFATs must do the following:
- Capture network traffic
- Analyze network traffic according to user needs
- Allow system users discover useful and interesting things
about the analyzed traffic
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NFAT Tasks
0 Traffic Capture
- What is the policy?
- What is the traffic of interest?
- Intermal/Externasl?
- Collect packets: tcpdump
0 Traffic Analysis
- Sessionizing captured traffic (organize)
- Protocol Parsing and analysis
= Check for strings, use expert systems for analysis
0 Interacting with NFAT
- Appropriate user interfaces, reports, examine large
quantities of information and make it manageable
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Honeynets/Honeypots
0 Network Forensics and honeynet systems have the same
features of collecting information about computer misuses
0 Honeynet system can lure attackers and gain information
about new types of intrusions
0 Network forensics systems analyze and reconstruct he attack
behaviors
0 These two systems integrated together build a active self
learning and response system to profile the intrusion
behavior features and investigate the original source of the
attack.
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Policies: Computer Attack Taxonomy
0 Probing
- Attackers reconnaissance
- Attackers create a profile of an organization's structure,
network capabilities and content, security posture
- Attacker finds the targets and devices plans to circumvent
the security mechanism
0 Penetration
- Exploit System Configuration errors and vulnerabilities
- Install Trojans, record passwords, delete files, etc.
0 Cover tracks
- Configure event logging to a previous state
- Clear event logs and hide files
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Policies to enhance forensics
0 Retaining information
0 Planning the response
0 Training
0 Accelerating the investigation
0 Preventing anonymous activities
0 Protect the evidence
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Example Prototype System: Iowa State University
0 Network Forensics Analysis mechanisms should meet the
following:
- Short response times; User friendly interfaces
0 Questions addresses
- How likely is a specific host relevant to the attack? What
is the role the host played in the attack? How strong are
two hosts connected to the attack?
0 Features of the prototype
- Preprocessing mechanism to reduce redundancy in
intrusion alerts
- Graph model for presenting and interacting with th3
evidence
- Hierarchical reasoning framework for automated inference
of attack group identification
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Example Prototype System: Modules
0 Evidence collection module
0 Evidence preprocessing module
0 Attack knowledge base
0 Assets knowledge base
0 Evidence graph generation module
0 Attack reasoning module
0 Analyst interface module
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Some Popular Tools
0 Raytheon’s SilentRunner
- Gives administrators help as they attempt to protect their
company’s assets
- Collector, Analyzer and Visualize Modules
0 Sandstorm Enterprise’s NetIntercept
- Hardware appliance focused on capturing network traffic
0 Niksun’s NetDetector
- Its an appliance like NetIntercept
- Has an alerting mechanism
- Integrates with Cicso IDS for a complete forensic analysis
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Types of Secure Network Systems
0 Internet Security Systems
0 Intrusion Detection Systems
0 Firewall Security Systems
0 Storage Area Network Security Systems
0 Network disaster recovery systems
0 Public key infrastructure systems
0 Wireless network security systems
0 Satellite encryption security systems
0 Instant Messaging Security Systems
0 Net privacy systems
0 Identity management security systems
0 Identify theft prevention systems
0 Biometric security systems
0 Homeland security systems
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Internet Security Systems
0 Security hierarchy
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- Public, Private and Mission Critical data
- Unclassified, Confidential, Secret and TopSecret data
Security Policy
- Who gets access to what data
- Bell LaPadula Security Policy, Noninterference Policy
Access Control
- Role-based access control, Usage control
Encryption
- Public/private keys
- Secret payment systems
Directions
- Smart cards
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Intrusion Detection Systems
0
An intrusion can be defined as “any set of actions that attempt to
compromise the integrity, confidentiality, or availability of a resource”.
0
Attacks are:
- Host-based attacks
- Network-based attacks
0
Intrusion detection systems are split into two groups:
- Anomaly detection systems
- Misuse detection systems
0
Use audit logs
- Capture all activities in network and hosts.
- But the amount of data is huge!
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Storage Area Network Security Systems
0 High performance networks that connects all the storage
systems
- After as disaster such as terrorism or natural disaster
(9/11 or Katrina), the data has to be availability
- Database systems is a special kind of storage system
0 Benefits include centralized management, scalability
reliability, performance
0 Security attacks on multiple storage devices
- Secure storage is being investigated
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Network Disaster Recovery Systems
0 Network disaster recovery is the ability to respond to an
interruption in network services by implementing a disaster
recovery palm
0 Policies and procedures have to be defined and subsequently
enforced
0 Which machines to shut down, determine which backup
servers to use, When should law enforcement be notified
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Public Key Infrastructure Systems
0 A certificate authority that issues and verifies digital
certificates
0 A registration authority that acts as a verifier for the
certificate authority before a digital certificate is issued to a
requester
0 One or more directories where the certificates with their
public keys are held
0 A certificate management systems
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Digital Identity Management
0 Digital identity is the identity that a user has to access an
electronic resource
0 A person could have multiple identities
- A physician could have an identity to access medical
resources and another to access his bank accounts
0 Digital identity management is about managing the multiple
identities
- Manage databases that store and retrieve identities
- Resolve conflicts and heterogeneity
- Make associations
- Provide security
0 Ontology management for identity management is an
emerging research area
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Digital Identity Management - II
0 Federated Identity Management
- Corporations work with each other across organizational
boundaries with the concept of federated identity
- Each corporation has its own identity and may belong to
multiple federations
- Individual identity management within an organization
and federated identity management across organizations
0 Technologies for identity management
- Database management, data mining, ontology
management, federated computing
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Identity Theft Management
0 Need for secure identity management
- Ease the burden of managing numerous identities
- Prevent misuse of identity: preventing identity theft
0 Identity theft is stealing another person’s digital identity
0 Techniques for preventing identity thefts include
- Access control, Encryption, Digital Signatures
- A merchant encrypts the data and signs with the public
key of the recipient
- Recipient decrypts with his private key
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Biometrics
0 Early Identication and Authentication (I&A) systems, were
based on passwords
0 Recently physical characteristics of a person are being used
for identification
- Fingerprinting
- Facial features
- Iris scans
- Voice recognition
- Facial expressions
0 Biometrics techniques will provide access not only to
computers but also to building and homes
0 Systems are vulnerable to attack e.g., Fake biometrics
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Homeland Security Systems
0 Border and Transportation Security
- RFID technologies?
0 Emergency preparedness
- After an attack happens what actions are to be taken?
0 Chemical, Biological, Radiological and Nuclear security
- Sensor technologies
0 Information analysis and Infrastructure protection
- Data mining, security technologies
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Other Types of Systems
0 Wireless security systems
- Protecting PDAs and phones against denial of service
and related attacks
0 Satellite encryption systems
- Pretty Good Privacy – PGP that uses RSA security
0 Instant messaging
- Deployment of instant messaging is usually not
controlled
- Should IM be blocked?
0 Net Privacy
- Can we ensure privacy on the networks and systems
- Privacy preserving access?
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OSI Model
0 The Open Systems Interconnection model (OSI model) is a
product of the Open Systems Interconnection effort at the
International Organization for Standardization.
0 It is a way of sub-dividing a communications system into
smaller parts called layers. A layer is a collection of
conceptually similar functions that provide services to the
layer above it and receives services from the layer below it.
0 On each layer an instance provides services to the instances
at the layer above and requests service from the layer below.
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OSI Model
0 The Physical Layer defines the electrical and physical specifications for
devices. In particular, it defines the relationship between a device and a
physical medium.
0 This includes the layout of pins, voltages, cable specifications, hubs,
repeaters, network adapters, host bus adapters (HBAs used in storage area
networks) and more.
0 The Data Link Layer provides the functional and procedural means to transfer
data between network entities and to detect and possibly correct errors that
may occur in the Physical Layer.
0 The Network Layer provides the functional and procedural means of
transferring variable length data sequences from a source to a destination
via one or more networks, while maintaining the quality of service requested
by the Transport Layer. The Network Layer performs network routing
functions, and might also perform fragmentation and reassembly, and report
delivery errors. Routers operate at this layer—sending data throughout the
extended network and making the Internet possible.
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OSI Model
0 The Transport Layer provides transparent transfer of data
between end users, providing reliable data transfer services
to the upper layers. The Transport Layer controls the
reliability of a given link through flow control,
segmentation/desegmentation, and error control.
0 Some protocols are state and connection oriented. This
means that the Transport Layer can keep track of the
segments and retransmit those that fail.
0 Although not developed under the OSI Reference Model and
not strictly conforming to the OSI definition of the Transport
Layer, typical examples of Layer 4 are the Transmission
Control Protocol (TCP) and User Datagram Protocol (UDP).
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OSI Model
0 The Session Layer controls the dialogues (connections)
between computers. It establishes, manages and terminates
the connections between the local and remote application. It
provides for full-duplex, half-duplex, or simplex operation,
and establishes checkpointing, adjournment, termination, and
restart procedures.
0 Presentation layer provides independence from differences in
data representation (e.g., encryption) by translating from
application to network format, and vice versa.
0 The presentation layer works to transform data into the form
that the application layer can accept. This layer formats and
encrypts data to be sent across a network, providing freedom
from compatibility problems. It is sometimes called the syntax
layer.
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Application Layer
0 APPC, Advanced Program-to-Program Communication
0 DNS, Domain Name System (Service) Protocol
0 FTAM, File Transfer Access and Management
0 FTP, File Transfer Protocol
0 Gopher, Gopher protocol
0 HL7, Health Level Seven
0 HTTP, Hypertext Transfer Protocol
0 IMAP, IMAP4, Internet Message Access Protocol
0 IRCP, Internet Relay Chat Protocol
0 LDAP, Lightweight Directory Access Protocol
0 LPD, Line Printer Daemon Protocol
0 MIME (S-MIME), Multipurpose Internet Mail Extensions and
Secure MIME
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Application Layer
0 NFS, Network File System
0 NIS, Network Information Service
0 NTP, Network Time Protocol
0 POP, POP3, Post Office Protocol (version 3)
0 SIP, Session Initiation Protocol
0 SMTP, Simple Mail Transfer Protocol
0 SNMP, Simple Network Management Protocol
0 SSH, Secure Shell
0 TELNET, Terminal Emulation Protocol of TCP/IP
0 VTP, Virtual Terminal Protocol
0 X.400, Message Handling Service Protocol
0 X.500, Directory Access Protocol (DAP)
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Network Protocols Technologies
0 Token Bus
0 Token Ring
0 X.25
0 Routing protocols
0 IEEE 802 Standards
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TCP/IP
0 In the TCP/IP model of the Internet, protocols are not as rigidly
designed into strict layers as the OSI model.[
0 TCP/IP does recognize four broad layers of functionality which are
derived from the operating scope of their contained protocols,
namely the scope of the software application, the end-to-end
transport connection, the internetworking range, and lastly the
scope of the direct links to other nodes on the local network.
0 The Internet Application Layer includes the OSI Application Layer,
Presentation Layer, and most of the Session Layer. Its end-to-end
Transport Layer includes the graceful close function of the OSI
Session Layer as well as the OSI Transport Layer. The
internetworking layer is a subset of the OSI Network Layer (see
above), while the Link Layer includes the OSI Data Link and Physical
Layers, as well as parts of OSI's Network Layer.
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IPV4
0 Internet Protocol version 4 (IPv4) is the fourth revision in the
development of the Internet Protocol (IP) and it is the first version of
the protocol to be widely deployed. Together with IPv6, it is at the
core of standards-based internetworking methods of the Internet.
IPv4 is still by far the most widely deployed Internet Layer protocol.
0 IPv4 is a connectionless protocol for use on packet-switched Link
Layer networks (e.g., Ethernet). It operates on a best effort delivery
model, in that it does not guarantee delivery, nor does it assure
proper sequencing, or avoid duplicate delivery. These aspects,
including data integrity, are addressed by an upper layer transport
protocol (e.g., Transmission Control Protocol).
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IPSEC
0 Internet Protocol Security (IPsec) is a protocol suite for securing
Internet Protocol (IP) communications by authenticating and
encrypting each IP packet of a data stream. IPsec also includes
protocols for establishing mutual authentication between agents at
the beginning of the session and negotiation of cryptographic keys
to be used during the session. IPsec can be used to protect data
flows between a pair of hosts (e.g. computer users or servers),
between a pair of security gateways (e.g. routers or firewalls), or
between a security gateway and a host
0 IPsec is a dual mode, end-to-end, security scheme operating at the
Internet Layer of the Internet Protocol Suite or OSI model Layer 3.
Some other Internet security systems in widespread use, such as
Secure Sockets Layer (SSL), Transport Layer Security (TLS) and
Secure Shell (SSH), operate in the upper layers of these models.
Hence, IPsec can be used for protecting any application traffic
across the Internet.
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TLS/SSL
0 Transport Layer Security (TLS) and its predecessor, Secure
Socket Layer (SSL), are cryptographic protocols that provide
security for communications over networks such as the
Internet. TLS and SSL encrypt the segments of network
connections at the Application Layer to ensure secure end-toend transit at the Transport Layer.
0 Several versions of the protocols are in widespread use in
applications like web browsing, electronic mail, Internet
faxing, instant messaging and voice-over-IP (VoIP).
0 The TLS protocol allows client/server applications to
communicate across a network in a way designed to prevent
eavesdropping and tampering. TLS provides endpoint
authentication and communications confidentiality over the
Internet using cryptography. TLS provides RSA security.
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TLS/SSL
0 In typical end-user/browser usage, TLS authentication is
unilateral: only the server is authenticated (the client knows
the server's identity), but not vice versa (the client remains
unauthenticated or anonymous).
0 TLS also supports the more secure bilateral connection mode
(typically used in enterprise applications), in which both ends
of the "conversation" can be assured with whom they are
communicating (provided they diligently scrutinize the
identity information in the other party's certificate). This is
known as mutual authentication, or 2SSL. Mutual
authentication requires that the TLS client-side also hold a
certificate (which is not usually the case in the enduser/browser scenario).
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DMZ
0 DMZ, or demilitarized zone is a physical or logical
subnetwork that contains and exposes an organization's
external services to a larger untrusted network, usually the
Internet.
0 The term is normally referred to as a DMZ by IT professionals.
It is sometimes referred to as a Perimeter Network.
0 The purpose of a DMZ is to add an additional layer of security
to an organization's Local Area Network (LAN); an external
attacker only has access to equipment in the DMZ, rather than
any other part of the network.
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DMZ
0 In a network, the hosts most vulnerable to attack are those
that provide services to users outside of the local area
network, such as e-mail, web and DNS servers.
0 Because of the increased potential of these hosts being
compromised, they are placed into their own sub-network in
order to protect the rest of the network if an intruder were to
succeed. Hosts in the DMZ have limited connectivity to
specific hosts in the internal network, though communication
with other hosts in the DMZ and to the external network is
allowed.
0 This allows hosts in the DMZ to provide services to both the
internal and external network, while an intervening firewall
controls the traffic between the DMZ servers and the internal
network clients.
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WAP
0 Wireless Application Protocol (WAP) is an open international
standard[for application-layer network communications in a
wireless-communication environment. Most use of WAP
involves accessing the mobile web from a mobile phone or
from a PDA.
0 A WAP browser provides all of the basic services of a
computer-based web browser but simplified to operate within
the restrictions of a mobile phone, such as its smaller view
screen. Users can connect to WAP sites: websites written in,
or dynamically converted to, WML (Wireless Markup
Language) and accessed via the WAP browser.
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WAP
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Instant Messaging
0 Instant messaging (IM) is a form of real-time direct text-based
communication between two or more people using personal
computers or other devices, along with shared software
clients. The user's text is conveyed over a network, such as
the Internet. More advanced instant messaging software
clients also allow enhanced modes of communication, such
as live voice or video calling.
0 IM falls under the umbrella term online chat, as it is a real-time
text-based networked communication system, but is distinct
in that it is based on clients that facilitate connections
between specified known users ("Contact List"), whereas
online 'chat' also includes web-based applications that allow
communication between (often anonymous) users in a multiuser environment
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VPN
0 A virtual private network (VPN) is a network that uses a public
telecommunication infrastructure, such as the Internet, to
provide remote offices or individual users with secure access
to their organization's network. It aims to avoid an expensive
system of owned or leased lines that can only be used by one
organization. The goal of a VPN is to provide the organization
with the same, secure capabilities, but at a much lower cost.
0 It encapsulates data transfers between two or more
networked devices not on the same private network so as to
keep the transferred data private from other devices on one or
more intervening local or wide area networks. There are many
different classifications, implementations, and uses for VPNs.
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Next Steps
0 Cloud computing security (sometimes referred to simply as
"cloud security") is an evolving sub-domain of computer
security, network security, and, more broadly, information
security. It refers to a broad set of policies, technologies, and
controls deployed to protect data, applications, and the
associated infrastructure of cloud computing.
0 Secuity issues fall into two broad categories: Security issues
faced by cloud providers (organizations providing Software-,
Platform-, or Infrastructure-as-a-Service via the cloud) and
security issues faced by their customers. In most cases, the
provider must ensure that their infrastructure is secure and
that their clients’ data and applications are protected while
the customer must ensure that the provider has taken the
proper security measures to protect their information.