Chapter 15 - D686 - Operating Systems

security

the protection of computer systems and data from unauthorized access, corruption, and breaches, ensuring data integrity, confidentiality, and proper user authentication

protection

rules and tools used to control who can access and use system resources, making sure only authorized users and processes can interact with files and data

attacker

a person trying to harm or gain unauthorized access to a computer system

attack

an attempt to harm or gain unauthorized access to a computer system

threat

a potential danger to the security of a system

security violations

unauthorized actions or breaches that compromise the confidentiality, integrity, or availability of a system, data, or network

denial-of-service (DoS)

blocking the normal use of a system by overwhelming it with requests that slow or stop its normal functions

masquerading

pretending to be someone else to gain unauthorized access

replay attack

repeating a valid data transmission to trick a system

man-in-the-middle attack

when an attacker secretly intercepts and alters the communication between two parties

session hijacking

taking control of a communication session between two parties

privilege escalation

gaining more privileges than a person or system should have

attack surface

The sum of the methods available to attack a system (e.g., all of the network ports that are open, plus physical access).

social engineering

A practice in which an attacker tricks someone into performing some task for the attacker (such as sending the attacker confidential information).

phishing

A class of social engineering attacks in which a legitimate-looking e-mail or website tricks a user into breaching confidentiality or enabling privilege escalation.

malware

software created to harm, exploit, or take control of computer systems

logic bomb

malware that activates when specific conditions are met

ransomware

malware that locks or encrypts your computer files and demands payment to unlock them

spyware

a type of malware that secretly collects information about a person or organization

trap door

a hidden way into a computer system left by an attacker for future access

back door

a secret method of accessing a computer system, often left by an attacker after a successful hack

Trojan Horse

a program that appears harmless but performs harmful actions

code-injection attack

an attack where harmful code is added to a good program

virus

a harmful piece of code that copies itself and can damage or change files and programs

worm

malware that spreads itself between computers without human help

secure by default

Describes a system or computer whose initial configuration decreases its attack surface.

zombie systems

Compromised systems that are being used by attackers without the owners' knowledge.

sniffing

An attack in which the attacker monitors network traffic to obtain useful information.

spoof

The imitation of a legitimate identifier (such as an IP address) by an illegitimate user or system.

distributed denial-of-service attack (DDoS)

An attack from multiple sources (frequently a botnet of zombies) with the purpose of denying legitimate use of the attacked resource.

cryptography

the practice of securing communication and data by restricting who can read or send information

keys

secret codes used in cryptography to encrypt and decrypt messages, ensuring only authorized parties can read the information

encryption

The use of cryptography to limit the receivers of a message or access to data.

symmetric encryption algorithm

A cryptography algorithm in which the same keys are used to encrypt and decrypt the message or data.

data-encryption standard (DES)

A cipher (algorithm for doing encryption and decryption) provided by the U.S. National Institute of Standards and Technology (NIST).

block cipher

A cipher that works on blocks of data (rather than bits).

advanced encryption standard (AES)

The NIST cipher designed to replace DES and triple DES.

asymmetric encryption algorithm

A cipher algorithm in which different keys are used for encryption and decryption.

public key encryption

A cipher algorithm in which different keys are used for encryption and decryption.

RSA

The most widely used public key cipher

public key

In asymmetric encryption algorithm, a key that can be distributed for encrypting and decrypting.

private key

In an asymmetric encryption algorithm, a key that must be kept private for use in authenticating, encrypting, and decrypting.

authentication

the process of verifying the identity of a person or device, ensuring they are who they claim to be

On UNIX systems, the _____ value is added to the password to ensure that if two passwords are the same, they result in different hash values.

salt

user authentication

The identification of a user of a computer.

password

A secret key, usually used to authenticate a user to a computer.

shoulder surfing

Attempting to learn a password or other secret information by watching the target user at the keyboard.

sniff

In network communication, to capture information by recording data as it is transmitted.

paired password

In authentication, a challenge-response set of secret keys, where only the correct response to the challenge provides authentication.

one-time password

A password that is only valid once.

passphrase

A longer, generally more secure password composed of multiple words.

personal identification number

A usually short and not very secure password composed of some combination of digits 0-9.

two-factor authentication

Authentication based on two separate sources of data (e.g., a brain providing a password and a finger providing a fingerprint).

multifactor authentication

Authentication based on two or more sources of data, with more sources generally providing stronger authentication.

What ensures system integrity and data preservation in computer systems?

Ensuring security

How does a breach of confidentiality differ from a breach of integrity? 

A breach of confidentiality involves unauthorized reading of data, while a breach of integrity involves modifying data.

Which method allows an attacker to intercept and alter communication between two parties?

Man-in-the-middle attack

How does the four-layered security model protect systems?

By securing each layer

What disguises itself as legitimate software to perform harmful actions?

Trojan horse

How does a logic bomb operate within a system

It activates under specific conditions

Which type of network attack involves taking control of an active communication session?

Session hijacking

What is the goal of a denial-of-service attack?

Disrupting system use

Which technique ensures data has not been altered during transmission?

Digital signatures

What converts data into a code to prevent unauthorized access?

Encryption