Cybersecurity mid term study

Linux Command Line

•The OG of how computers were operated before GUI (Graphic User Interface)

•Still used by technical people, hackers, and Linux users

•Allows you to run programs, do final manipulation, modify/view network traffic, and more

Relative path

The current directory you are in, does NOT start with the root directory (ex. Documents/MyFiles)

Absolute path

The whole path starting from the root directory (ex. /root/home/student)

Virtual Machines

Understand what they are, what a hypervisor is, and the layering between the hypervisor, guest OS, host OS, and hardware

Confidentiality (CIA triad)

Protecting data from unauthorized access

Integrity (CIA triad)

Ensuring data is not manipulated or changed in transit

availability (CIA triad)

Ensuring data is available for its users

Vulnerability

A flaw or weakness in a system, software, computer component

Threat

The person or thing acting against a system, software, or computer component with the intentions of causing damage

Risk

The existence of both a threat and a vulnerability; Vulnerability & Threat = Risk

Controls

•The things that we do as cybersecurity professionals to combat vulnerabilities and deter threats to overall reduce our risk

•Risk = Vulnerability Threat Impact

Countermeasures

•Do one of the following: Protect, Detect, or React

•Fall into 3 categories

•Physical, Ex. Hiring security guards

•Logical/Technical, Ex. Encrypting network traffic

•Administrative, Ex. All users must take phishing training

Common Cyber Threats:

APT’s, Social Engineering, Phishing, Ransomware, DDoS

Identification

Associating an identity with a subject (Claiming my name is John Doe)

verfication

Confirming who you are (I own a drivers license which proves I am John Doe)

Authentication

Validating that you are who you say you are through a method of verification (I give my drivers license to the bouncer who see the picture, my name, and authenticates me)

Authorization

Associating rights or capabilities with a subject (I am authenticated into the club but am only authorized to stay on the first floor)

Factors of identification

•Something you know (User ID and Password)

•Something you have (key or card)

•Something you are (fingerprint, face ID)

MFA

2 or more of these (keep in mind 2FA is two of these, MFA is multi = 2 or more so potentially 3, 4, etc.)

password rules

•remember that 4-digit password = 4^10 different possibilities, 10-digit password with lowercase alphabets and number = 10^36 different possibilities

Common attacks against identification methods

Dumpster diving, shoulder surfing

Biometrics

something you are, generally considered the strongest form of authentication since it is unique to every person and hard to “steal”

False Acceptance Rate (FAR)

the rate at which we accept an illegitimate user; false accepting the wrong person

False Rejection Rate (FRR)

the rate at which we reject a legitimate user; falsely rejecting the right person

Access Control

What the system enforces you to do (policy-based)

Defense-in-Depth

Implementing security controls on all layers(Policy, Physical, Network, Computer, Application, and Device)

Principal of Least Privilege

Only give people the permissions they need to perform the task at hand

Subjects

the thing/people who receive access (User George Mason)

Objects

the thing which subjects are receiving access to (File 1)

Discretionary Access Control (DAC)

owner decides access

Mandatory Access Control (MAC)

Label-based, most strict of all 5, common in government and military settings

Role-Based Access Control (RBAC)

Based on a user's role (Department, location, seniority, work duties)

Rule-Based Access Control

Rule-based (can only access between 9 AM and 5 PM)

Attribute Based Access Control (ABAC)

Based off certain attributes of users(role, tasks), the resource(critical, public), or the environment(night, morning)

Access Control Matrix

A matrix containing permissions that are associated between subjects and objects.

Privilege Separation

Ensuring two groups or users don’t overlap in permissions and don’t cause a conflict of interest.

Access Control List

Breaks down this matrix and represents a single object and what permissions the subjects have for that object.

Auditing

Reviewing what was actually done (log review and monitoring, assessments, inventory, etc.)

Who’s accountable?

Everyone, but each person has a specific role to play.

Vulnerability Assessment

Scanning for vulnerabilities and weakness

Penetration Test

Actually exploiting those vulnerabilities found in the vulnerability assessment

Responsible (RACI)

The person assigned to do the work

Accountable (RACI)

The person who has the authority to assign or delegate work, this is the person people go to for answers.

Consulted (RACI)

This person must be consulted before the work is started, needs to give their blessing

Informed (RACI)

This person just wants to be kept in the loop on what’s happening

Cryptology

The study of secret codes

Cryptanalysis

The study of breaking codes

Cryptography

The study of making codes

Encryption

Turning some text from legible (plaintext) to secret (ciphertext)

Decryption

Turning secret (ciphertext) to legible text (plaintext)

Asymmetric

2 keys, a public that is shared between the sender and receiver, and a private which both the sender and receiver have their own unique key which is the only thing that can be used to decrypt the message

Symmetric

1 public shared key, typically exchanged through a secure channel or method such as the Diffie-Hellman Key exchange

Hashes

1-way cryptographic computation which is focused on keeping things secure, cannot be broken, but can be found from rainbow tables. Hashes will always generate the same hash for the same input

Digital Signature

Verifying the integrity of a message by both parties creating a hash and matching it up to see if it matches. If it does, integrity has not been compromised, if it doesn’t, should investigate that.

Substitution (Cipher method)

One letter in the alphabet is substituted for another, ex. Caesar Cipher. Ex. A ROT3 means A -> D, B -> E, C -> F, and so on

Transposition (Cipher method)

Plaintext is repositioned, but letters are left unchanged, ex. Hello -> elhol

SHA1

Produces 160-bit hash, pretty insecure due to collision

SHA-256

Produces a 256-bit hash, still used today; collision is still possible but unlikely

SHA-512

Produces a 512-bit hash, best security, but not widely used

Secure Shell protocol (SSH)

remotely login and perform command-line executions on another machine. This is fully encrypted traffic between the two hosts. Operates on Port 22

Side Channel Attacks

Using physical data of the computer, such as CPU cycles, to get an idea of how data is being encrypted or decrypted, for ex. If a hacker sees that one user's CPU is consistently decrypting messages in 0.001s, they can maybe assume it is an X algorithm being used.

Rainbow Attacks

Cracking a password based on the hash referenced to a table of already known hashes. This database is referred to as a rainbow table.

Steganography

The technique of hiding data within an ordinary file to avoid detection.