Embedded Files
The Internet and WWW
The Internet is an infrastructure (components, cables, etc.) and WWW is the collective term for all the websites and web pages
URL
Text-based addresses to access web page/site
Typed in the address bar of a Browser
Components
protocol
domain name
file name
Process:
User open a Web browser
types the URL
Browser sends the URL to the Domain Name Server (DNS)
DNS looks through its database
if not found send to another DNS (until found)
if found returns the IP address of the web server
HTTP
Hypertext Transfer Protocol
set of rules for transferring files, such as text, graphic images, sound, video, and other multimedia files, on the World Wide Web.
HTTP uses a server-client model.
HTTP Request / Response (Working of HTTP)
Standard with a layer of security
SSL (Secure Socket Layer)
TLS (Transport Layer Security)
Communication between clients and servers is done by requests and responses
A client (a browser) sends an HTTP request to the web
A web server receives the request
The server runs an application to process the request
The server returns an HTTP response (output) to the browser
The client (the browser) receives the response
Web Browser
Displays web pages by rendering HTML
HTML: language used to create a website. Example tags are <head> and <body> (2023)
Functions:
Storing bookmarks/favourites
Recording user history
Allowing use of multiple tabs
Providing navigation tools
Providing an address bar
Managing protocols // checking digital certificate
Send URL to DNS
Sends a request to the IP address/web server (to obtain the contents of a webpage)
Runs active script/JavaScript/client-side script
Allows files to be downloaded from website/internet
Stores & manages Cookies
Cookies
Small text files that store data (about the user)
can be disabled in your browser settings
not programs (cannot perform any operations)
are not viruses or malware.
Examples
Storing your Username and passwords (for email, social media, etc.)
Storing your bank debit/credit card details
Storing products in your virtual shopping cart
Store and maintain user preferences on a website
Track user behaviour (analytics)
Store items in shopping baskets
Help advertisers show relevant website advertisements
Types
Session Cookies
contains information that is stored in a temporary memory location and then subsequently deleted after the session is terminated or the web browser is closed
No personal user identification
Persistent Cookies
permanent
has an expiry date
Allows websites to remember usernames and passwords
Recognizes user every time
Saves items to the Virtual shopping Basket
Track internet habits, website histories, or bookmarks/favorites
Target users with advertising
Stores user’s preferences
Saves the progress of online games/quizzes
Allows social networking sites to recognize users and preferences
Allows different languages to be used on the webpages
Digital Currency
exists electronically, Usually encrypted
When you pay for products and services using the internet
electronic form of fiat money
Most popular are Credit/Debit cards, online banking using Paypal or via smartphone
Digital Currency relies on the “Central Banking System”
The problem with centralization is maintaining confidentiality and security
Crypto currency
Decentralized (no authority like a bank)
Payments are encrypted
Blockchain is used to keep track of payments (using Digital ledger) (2023)
It keeps a series of time-stamped records
Brute force attack
Definition: Trial and error to guess a password, Combinations are repeatedly entered until correct password is found, Can be carried out manually or automatically by software. Steal/view/accessDelete/Change/Lock/Encrypt data (2023)
Prevention: Enable two-factor authentication, Setting a limit for login attempts, Drop-down boxes, longer more complex passwords, biometric passwords (biological data-Fingerprint/retina) and use of strong encryption techniques
Data interception
Definition: form of stealing data by tapping into wired/wireless communication links with the intent to invade privacy and obtain sensitive information. Done using packet sniffer(installed onto a piece of hardware that the packets will pass through)
Prevention: Use firewalls, classification of sensitive data, complex password
Distributed Denial of Service
Definition: It is the useless traffic flooding the server often causing many compromised systems under the control of the attacker with an intent to invade privacy. A perpetrator creates botnets.
Recognition of DDOS: Slow network performance, Inability to access certain websites, Large number of spam emails reaching the user’s email account Designed to deny people access to a website
A large number/numerous requests are sent (to a server) all at the same time
The server is unable to respond/struggles to respond to all the requests
The server fails/times out as a result
Prevention: Enable two-factor authentication, longer more complex passwords, firewall, proxy servers, antimalware, and use of strong encryption techniques
Hacking
Definition: Act of gaining illegal access to a computer system/account without permission which can lead to theft of info and identify theft.
Prevention: Anti-hacking software, strong password, firewall
Malware (Virus, Worm, Spyware, Trojan horse, Adware, Ransomware)
Virus
Definition: A dangerous program code with the intention of corrupting data and malfunctioning of the computer.
Prevention: Anti-virus software, up-to-date virus scanners, and firewall
Worms
Definition: Stand-alone malware that can self-replicate with the intention to damage other computers and networks too.
arrives as an attachment usually
Recognition and symptoms: freezing/crashes, slow performance, firewall warnings, system error messages
Prevention: avoiding public or unsecured wifi channels, anti-malware software, scanning PC regularly, backing up files, not using open/public wifi
Trojan horse
Definition: - Appears as legitimate software with malicious instructions embedded within it.
Arrives through an email attachment or downloaded from an infected website.
sends personal data (including IP addresses, and passwords) to cyber criminals once installed
Spyware/ransomware is often installed on the user’s computer through trojan horse malware
Prevention: Do not download free trial software - Do not click on unknown attachments, and keep the firewall updated, regular scanning, use spam identifying services
Spyware
Definition: This software gathers information by monitoring a user’s activities carried out on their computer. For eg: pegasus
Prevention: Install anti-spyware software, Be careful while entering your personal information on a public computer
Adware
Definition: It’s the least dangerous malware but attempts to flood your browser with unwanted advertisements
It can defeat most anti-malware
Prevention: Keep pop-up blockers on, be alert to popups
Ransomware
Definition: This malware restricts the access of the computer and encrypts all the important information until a ransom is paid. It can install on a user’s computer by way of a Trojan horse or through social engineering.
Prevention: Avoiding phishing emails, keeping the system updated, usual security methods
Phishing
Definition: Sending out legitimate-looking emails designed to trick the recipients into giving their personal details to the cybercriminal
Prevention: Be aware of new phishing scams, regularly run anti-phishing toolbars on browsers, look out for the green padlock symbol
Pharming
Definition: Redirecting a user to a fake website in order to illegally obtain personal data about the user without their knowledge, unlike phishing, pharming is initiated without needing any action by the user. Manipulate the DNS server
Prevention: Antivirus software, Checking the spelling and tone of the email/website/URL, modern browsers alert pharming attacks
Social engineering (2023)
Definition: Manipulating and deceiving people into providing confidential/personal information, breaking normal security procedures (such as giving away the password) in order to gain illegal access to the computer systems or to place malware on the computer
Prevention: Checking for spelling errors in emails, being emotionally strong and in your senses, longer complex password, two-factor authentication
Access levels (2023)
Providing users with different permission for the data
Limiting access to reading data limiting the data that can be viewed
Limiting access to editing data // limiting the data that can be deleted / changed
Firewalls
Firewalls
Hardware or software based security layer that is positioned between the internet and network/user device.
Examines incoming/outgoing traffic
Identifies suspicious file/phrases and notifies administrator if anything is flagged
Acts as a gateway to the internet
White lists/blacklists websites/applications are blocked
All the administrator to monitor/limit bandwidth
Prevents hackers/viruses
Proxy Servers
Proxy Servers
Intermediary piece of hardware between network/user and the internet that CACHES (remembers) commonly viewed websites which can speed up the user experience of a website.
Filters internet traffic
Keeps the user’s IP hidden (masking)
Acts as a firewall if a firewall isn’t present on a network (limited functionality)
Using Proxy servers and Firewalls, we can prevent DoS attacks or Web server hacking
Similarities between Firewall and Proxy Servers
Check incoming and outgoing signals // filter traffic
Store whitelist/blacklist
Block incoming/outgoing signals
Both block unauthorised access
Keep a log of traffic
Both can be hardware or software (or both)
Differences between Firewall and Proxy Servers
Proxy can hide user's IP address, firewall does not hide the user's IP address
Proxy intention is to divert attack from server, firewall is to stop unauthorised access
Proxy protects a server, firewall protects individual computer
Proxy examines/processes requests for a website but a firewall does not (checks type of signal) // Proxy processes client-side requests
whereas firewall filters packets, Proxy transmits website data to the user
Proxy allows faster access to a web page using cache, but a firewall does not (allow faster access or have cache)
Proxy can hide internal network from internet, but a firewall cannot
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