CodeHS Cybersecurity Level 1 Certification

https

secure sites (uses port 443)

file system

organizational file storage system using compression, encryption, permissions, and journaling

FAT32

compatible with Windows, Mac, Linux; used for USB and memory cards, 16 TB limit

NTFS (New Technology File System)

Windows only, 1 exabyte limit

Ext4

Linux only, 1 exabyte limit

HFS (Hierarchical File System)

Mac only, 8 exabyte limit

cache

collections of files and data saved to increase browser speed

ls

show current directory contents (Linux/MacOS)

dir

show current directory contents (Windows)

cd

change directory (include ..

pwd

show current directory path (Linux/MacOS)

ps

displays running processes (Linux/MacOS)

cp

copy file (Linux/MacOS)

mv

move file (Linux/MacOS)

column

attribute or piece of information

row

one entry in a table, also called a record

SELECT

asks for row(s) from table in database

WHERE

allows rows to be filtered by a condition

<>

means 'not equal to' in SQL

Error-based SQLi

website returns an error to allow further exploration

Union-based SQLi

adding a condition that always returns true to extract additional information

blind SQLi

attacker steals data by asking a series of true/false questions

ASCII

encoding scheme for characters using 8 bits

bandwidth

capacity of data transfer measured by bitrate

bitrate

number of bits a system can send per second

latency

time it takes a bit to travel from sender to receiver

IPv4

IP address expressed as 4 groups of 8 bits (0.0.0.0 - 255.255.255.255)

IPv6

new 128 bit version of IP expressed as 8 groups of 16 bits

DNS (Domain Name System)

translates between names and IP addresses

UDP (User Datagram Protocol)

one-way communication, does not verify everything was sent properly or correctly

HTTP (HyperText Transfer Protocol)

standardizes language for sending/receiving web resources to/from servers

Port 80

HTTP used for communicating across World Wide Web (unsecured)

Port 443

HTTPS - used for sending encrypted information to protect data

Port 22

SSH (Secure Shell Protocol) for secure remote logins

Ports 20/21

FTP (File Transfer Protocol) sending and receiving files between computers

Port 23

Telnet - used for remote logins using terminal or CLI

Port 25

SMTP (Simple Mail Transfer Protocol) - used to send emails

Port 110

POP3 (Post Office Protocol) - receives emails on a single device and deletes them from server

Port 143

IMAP (Internet Messages Access Protocol) - receives emails and syncs across multiple devices

Port 53

DNS (Domain Name System) - receives domain name requests and provides corresponding IP address

Port 67/68

DHCP (Dynamic Host Configuration Protocol) - assigns IP address to a network connected device

Port 161/162

SNMP (Simple Network Management Protocol) - changes configuration parameters of routers, switches and network devices

frequency bands

ranges of radio waves used to transmit data

2.4 GHz

slower, longer range, penetrates objects, more interference; 11 channels for normal use in US

5.0 GHz

faster, shorter range, cannot penetrate solid objects, less electronic interference

802.11ac

fastest wireless standard as of 2014

RADIUS (Remote Authentication Dial In User Service)

networking protocol that provides AAA management

netsh

enables users to change network settings (Windows)

networksetup

enables users to change network settings (Mac)

nbstat

displays TCP/IP statistics and information (Windows)

netstat

displays TCP/IP statistics and information (Mac)

BIOS

firmware that runs programs strictly to start up your computer

solid-state drive (SSD)

fast access computer storage device

graphics processing unit (GPU)

device designed to speed up image creation and display

network interface card (NIC)

allows computer to connect to network with built in network port

driver

group files that allows device to communicate with OS

NFC (Near Field Communication)

enables short range communication between compatible devices

file server

network storage with powerful network adapters

WAN

wide area network (like the Internet)

WLAN

wireless LAN that uses radio frequency technology

VLAN

virtual LAN that allows for the setup of separate networks

interpreted language

translates and executes program code line by line into machine code

compiled language

compiles entire code into machine code to be run later

markup language

uses tags to format and define elements within a document

query language

Used to make queries, or searches, in databases and information systems.

assembly language

very close to machine code for a specific type of processor

scripting language

commands within a file capable of being executed without being compiled

variable

identifier for data that can be changed at any time

constant

an identifier for data that cannot be changed

integer

number WITHOUT a decimal component

float

number WITH a decimal component

string

text or a sequence of letters, numbers, punctuation, spaces, etc

char

contains a single character or punctuation

array

fixed container that stores an ordered collection of items

vector

resizable container that stores an ordered collection of items

object

can store combinations of keys and values where the value can be accessed by its associated key

methods of an object

defines what an object can do