CIS 2337 Midterm review

Computer Security

Methods, techniques, ans tools used to ensure a computer system is secure.

Critical Infrastructure

Infrastructure whose loss/impairment would have severe repercussions.

Elite Hacker

Skills necessary to discover and exploit new vulnerabilities.

Hacker

someone who accesses a computer or network illegally

Hacking

Intentionally accesses a computer without authorization or exceeds authorized access.

Hacktivist

a politically motivated hacker who uses the Internet to send a political message of some kind.

Highly structured threat

Threat backed by the time and resources to allow any form of attack

information warfare

the use of information security techniques, both offensive and defensive, when combating an opponent

Morris worm

One of first internet crimes. Infected computer systems until they could no longer run.

script kiddie

An unskilled user who downloads automated attack software to attack computers

Structured threat

Threat with reasonable financial backing and can last a few days or more. More time to penetrate and attack.

Unstructured Threat

Threat with no significant resources/ability

A friend of yours has just been hired by an organization as its computer security officer. Your friend is a bit nervous about this new job and has come to you, knowing that you are taking a computer security class, to ask your advice on measures that can be taken that might help prevent an intrusion. What three things can you suggest that are simple but can tremendously help limit the possibility of an attack?

C I A - Confidentiality, integrity, and availability

Discuss the major difference between a target of opportunity attack and a targeted attack. Which do you believe is the more common one?

A target of opportunity attack is usually victim due to HW/SW vulnerabilities. A targeted attack is when the victim is specifically targeted for some reason.

Target of opportunity attack is more common because most attackers exploit vulnerabilities.

Reread the various examples of computer crimes at the beginning of this chapter. Categorize each as either a crime where the computer was the target of the criminal activity or a crime in which the computer was a tool in accomplishing the criminal activity.

1)The Morris Worm (November 1988) - target

6) Solar Sunrise (February 1998) - target

7) The Melissa Virus (March 1999) - tool

8) The Love Letter Virus (May 2000) - tool

9) The Code Red Worm (2001) - tool

11) The Slammer Worm (2003) - target

13) Conficker (2008) - target

Property

"No-write-down" rule; doesn't allow user to write to a file with a lower security class, preserving confidentiality

Access control

Ability to control whether a subject can interact with an object

Auditability

The property of an item that makes it available for verification upon inspection.

availability

Devices must be present and accessible when subject wants to access them.

Bell-LaPadula security model

Addresses data confidentiality

Biba security model

Integrity issues; data with higher integrity level is more reliable and accurate

Brewer-Nash model

Controlling read and write access based on conflict of interest rules

Clark Wilson security model

Uses transactions as a basis for rules

Complete Mediation

Every access attempt is checked

Confidentiality

Ensures that those who have permission can access data

Default Deny

Deny access by default and grant access when specific permissions exists.

diversity of defense

Different kinds of defense

Economy of Mechanism

Keep it simple stupid

Fail-safe defaults

If something fails, it goes to a safe state

Hacking

Attempts to gain unauthorized entry into a computer system or network.

Host Security

Protect each individual computer and device

Implicit Deny

AKA default deny

Integrity

Generation and modification of data

Layered Security

Using multiple diverse defense at differing points

Least common mechanism

Mechanisms used to access resources should be dedicated not shared

Least privilege

Subject should only have NECESSARY rights and privileges to perform task

Low-Water-Mark policy

(No red down) prevents unauthorized modifications

Network security

Protection of computers and devices within a network

Nonrepudiation

Ability to verify a msg has been sent and received and the sender can be ID and verified

Open Design

Protection of an object should not rely upon secrecy of protection mechanism

operational model of computer security

protection = prevention + (detection + response)

Phreaking

Hacking used by telephone companies to operate its network

Psychological acceptability

User's acceptance of security measures

Ring policy

Allows any subject to read any object regardless of level of integrity and without lowering integrity level

Security through obscurity

Protection by hiding it

Separation of duties

Separation of privilege among people

Separation of privilege

Protection mechanism that uses more than one piece of info to make access decisions

Simple security rule

No subject can read info from an object with a higher security classification

Your company has decided to increase the authentication security by requiring remote employees to use a security token as well as a password to log onto the network. The employees are grumbling about the new requirements because they don't want to have to carry around the token with them and don't understand why it's necessary. Write a brief memo to the staff to educate them on the general ways that authentication can be performed. Then explain why your company has decided to use security tokens in addition to passwords.

An extra layer of authentication can help prevent intrusions since they have been on a rise.

The new CEO for your company just retired from the military and wants to use some of the same computer systems and security software she used while with the military. Explain to her the reasons that confidentiality-based security models are not adequate for all environments. Provide at least two examples of environments where a confidentiality-based security model is not sufficient.

Information system model helps bridge gap between what is said and implementation

Describe why the concept of "security through obscurity" is generally considered a bad principle to rely on. Provide some real-world examples of where you have seen this principle used.

It's like hiding money under a bed. The only protection is that other do not know where it is.

Hash

The unique signature created by a hashing algorithm.

collision attack

Attacker's finds 2 different messages that hash to the same value

Cryptology

Study of cryptography and cryptanalysis, study of secrets

cryptography (n)

secret writing; the encoding and decoding of messages

Cryptosystem

Any system that encrypts and decrypts

Cryptanalysis

Process of analyzing available info in an attempt to decrypt

Differential Cryptanalysis

Comparing input plaintext to output ciphertext to determine the key used to encrypt

Linear Cryptanalysis

Put plaintext through simple cipher to try and deduce what the key likely is.

digital signature

a means of electronically signing a document with data that cannot be forged

digital rights management (DRM)

protection of digitally distributed intellectual property

Multiple Encryption

The use of multiple layers of encryption to improve encryption strength.

Entropy

Randomness in a system

Confusion

Principle to affect the randomness of output

Difussion

Change in one character of plaintext should cause multiple changes in ciphertext

Cryptographic system

Process of turning plaintext and ciphertext using an algorithm and a key

Algorithm

A specific repeatable method of performaning a task

Perfect forward secrecy

Property of public keys system where the key derived from another key is not compromised

Shared secret

Sender and receiver have same key

Ephemeral Keys

Keys used only once

Key space

A set of every possible key value

Key stretching

Mechanism that takes weak keys and stretches them to make the system more secure.

Key Management

The process of controlling the secret keys used in encryption.

Cipher

Pair of algorithm and key used to communicate secretly

Shift cypher

One letter is shifted a set number of places for another letter ; used by Romans

Stream cypher

Enciphers plaintext in a stream bit by bit; RC4

Vigenere cipher

an advanced type of substitution cipher that uses a simple polyalphabetic code. Depends on a password.

Block cypher (DES)

Segments input into blocks and adds extra padding to last block.

Data encryption standard

Standard cryptographic algorithm (1973)

Trapdoor functions

Functions difficult to process without the key but easy to process when you have the key

Transportation

The changing of the order of items

Steganography

Hiding the existence of data within a text, audio, image, or video file.

Pseudorandom numbers

A number that appears to be random but is generated by a formula.

NIST

National institute of standards and technology

SHA

Secure Hash Algorithm; hash algorithms of NIST and NSA

digital certificate

an electronic document that associates credentials with a public key

Certificate Practice Statement (CPS)

A technical document that describes in detail how the CA uses and manages certificates.

Certificate Server

Service that issues certificates

Registration Authority (RA)

This performs certificate registration services on behalf of a CA.

Local registration authority (LRA)

Closer to end users

End-entity certificates

Issues by CA to a specific subject

CA certificate

issued by one CA to another CA; the second CA can, in turn, then issue certificates to an end entity

Cross-certification certificate

Mechanism in which one CA can issue certificate allowing its users to trust another CA

How does polyalphabetic substitution work

Depends on a password; when the password matches it enciphers, if not long enough it repeats until it matches

Why is asymmetric encryption called public key encryption?

It uses 2 keys: a private key and a public key

Describe cryptanalysis

Process of attempting to break a cryptographic system.

Describe pros and cons of establishing a key archiving system for a small/medium business

Pros: save resources/time, efficiency, recycle and monetize, optimum performance and storage, cheaper, backup and recovery is better, less overhead, and archives data

Cons: will archived be accessible in future?, storage mechanisms will change over time, natural disasters

Why implement a Public key infrastructure solution?

Enables the creation of a trustee environment through the internet.

Steps to verify a certificates validity.

Keys are exchanged by passing certificates

How do you obtain a certificate?

Register

Public and private key lair generated

Key pair stores in key store

Copy of public key and data sent to CA

CA generate digital certificate containing public key and other info

Certificate sent to user