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4. Security and Encryption

All Past Paper Questions: https://docs.google.com/document/d/1ivd2MdIj0b15Y9NipaAJUMKutLsAbF6eisv1y07ACmg/edit?usp=sharing

Safety​

Issues​

  • in the form of:
    • Issue
      • Prevention
  • overloading sockets causing overheating
    • CO2 file extinguider in room
    • seperate sockets for each plug
  • water split into live wires & cause electrocution
    • do not allow food and drinks into the computer room
    • ensure all wires are properly insulated
  • trailing cables can cause users to trip up and injure themselves
    • ensure proper trunking is in place
  • heavy objects can all off tables can cause injury
    • use strudy stable desks
    • dont place heavy objects in the corner of desk

Accidents​

  • can result in serious injury
  • issues
    • fire hazards
    • electrocution
    • personal injury
  • can be caused by
    • overloading sockets (causing overheating)
      • use a multi-pin adaptor,
      • use a circuit breaker
    • overheating of computers
    • water split into live wires
    • handling bare wires
    • trailing cables can cause users to trip up
      • ensure cables are tied up
    • heavy objects falling off tables
      • use sturdy tables
      • ensure equipment is not at edge of the table

Health​

  • health issues
    • arise from long term use of computers
    • issues
      • RSI (Repitive Strain Injury)
        • from continual usage of mouse/keyboard
        • take regular breaks
        • use ergonomic mouse/keyboards
      • CTS (carpal tunnel syndrome)
        • from prolonged use of mobile phones
        • keeping the elbow bent
        • use ergonomic mouse/keyboards
        • use headphones
      • lower back pain
        • sitting in same position for long periods of time
        • use ergonomic furniture
      • eye strain
        • staring at monitor for long times
        • take regular breaks
        • use anti glare screens
      • headaches
      • upper back pain
      • neck pain
        • position monitor at eye level and proper distance
      • shoulder pain
      • etc...
    • can be caused by
      • typing at a keyboard continuously
      • gripping a mouse and repetitive clicking
      • sitting in the same position (with a bad posture) the whole day
      • staring at a computer screen all day
      • glare from screen

e-Safety​

  • protecting data

    • physical protection
      • security gaurd to prevent unauthorized people
      • swipe cards
    • electronic protection
      • biometric data
        • unique biometric features, like fingerprint or retina, thats unique to each individual
      • passwords
        • hard for hacker to guess or bruteforce (or crack)
      • firewall
        • whitelist: only access connections from trusted IPs
      • access levels
        • give each user a different access level to the stuff in the network
      • use a VPN
        • more secure if the vpn is encrypted,
        • specially when using a public network

  • other methods of keeping data secure

    • use minimum amount of confidential information
    • use anonimized information whenever possible
    • secure dispose personal information
    • have access control systems
      • eg: RBAC
    • secure the network with firewalls

  • when sharing images

    • remove geo-tags from images
    • or any other juicy EXIF data

  • parents should tell children to

    • dont give out personal info
      • home address
      • parents name
      • school name
    • use a nickname online
    • dont sent images of themselves(+family) to unknown people
    • make sure your privacy settings are secure
    • inform parents if being cyber-bullied
    • dont meet up with random strangers

  • parents should

    • talk to child about what they are doing
    • keep computer visible
    • teach child to block people
    • let the child know its never too late to let the parents know

  • personal data, kept confidential

    • can commit identity theft
    • can trick banks into performing unauthorized transfers
    • if publicly shared as not home, burglars may come
    • sharing personal views about politics & religion can affect job opportunities
    • subjected to credit card scams
    • insurace could be denied depending on whats shared
    • can sell data like medical info to others
    • OTHER
      • company secrets can be sold to rival companies
      • national secrets can be used by rival powers

  • when students use the inernet

    • social media
      • unauthorized access to perosnal information
      • grooming
      • sharing personal images without consent
      • inappriate communication
      • cyber-bullying
    • other
      • exposed to unsuitable videos
      • innacurate information
      • plagiarism and copyright infringment
      • illegal media download
      • innappropriate content

  • schools's e-safety policy

    • discourages access to illegal content
    • discourages piracy
    • teaches that unauthorized access to personal information might occur
    • reduces risk of grooming
    • reduces inappropriate communication
    • discourages sharing personal information without consent
    • teaches students to evaluvate accuracy of information
    • discourages plagirism and copyright infringement

Web​

HTTPS​

  • advantages
    • message cannot be read by third party
    • certificate gaurantees that information is from expected domain
    • gaurantees data is sent to the right place
    • makes MITM attacks difficult
    • search engines shows HTTPS sites first
    • green-padlock in browser tells the site uses HTTPS
  • disadvantages
    • uses server resources for encryption
    • introduces latencies
    • SSL takes longer to setup more round trips
    • browser caching doesnt work properly
      • modern browsers run slowly without caching
    • need to buy SSL certificates from certificate authorities
      • we can also make our own
      • but others dont trust it
      • so, warnings can arise
    • there are proxy caching problems
    • everything is encrypted, including packet headers and contents
    • any caching that might have happened between two points at which data is encrypted and decrypted is blocked
    • if the private key is lost, its extremely hard to recover
    • extra storage space for client/server
    • takes longer to transmit encrypted data
    • takes longer to decrypt the encrypted data

SSL/TLS​

  • encryption protocols can be used

  • all major web browsers currently in use support TLS

  • client-server applications use SSL/TLS to prevent eavesdropping

    • by using encryption protocols
    • so, technically, can secure carry out bank transactions

  • are used in web browsing, email, internet faxing, messaging, VoIP, etc...

  • SSL

    • secure sockets layer
    • is old technology

  • TLS

    • transport layer security
    • successor to SSL

  • how TLS/SSL is used in client-server networks?

    • TLS is used for applications that require data to be securely exchanged
      • eg: browser sessions, file transfers, etc..
    • server sends digital certiciate to client
      • to open a TLS connection
      • client needs to obtain the public key
      • public key is found in digital certiciate
      • digital certificate authenticates the server to the client
        • client checks if certiciate was issued from a trusted CA
        • check whether the server is legitamate owner of public & private keys
    • client does TLS handshake
      • client tells server what version of SSL/TLS it uses
      • and lsit of encryption protocols its able to use
      • client tells the server it wants to setup a communication channel
      • handhsaking occurs before the transfer of data can take place
      • server tells the client the type of encryption it has chosen from the client's list

Encryption​

  • define

    • data is scrambled
    • converting information so that data is irreversible

  • when encrypted

    • its useless even if the message is intercepted
    • the message is meaningless
    • data is scrambled
    • cannot unscramble without key

  • disk encryption

    • advantages
      • other users cannot open (without permission)
      • file remains encrypted even if moved
      • can be used on any files
      • users with permissions should first decrypt and then use
      • other users get an error message
    • disadvantages
      • files lost if (irreversibly)
        • password is lost
        • OS fails
        • OS is re-installed

  • email encryption

    • advantages
      • protects contents from hackers
      • just passwords on email accounts are not enough
      • email providers never encrypts email (+attacthments)
      • recipients mail server may not be secure
      • without encryption, email sent as plain text
      • with encryption, email is scrambled and sent, so, unreadable
        • must unscramble and read contents
    • disadvantages
      • hackers can intercept and delete emails
      • encrypting with private keys requires key to sent, which can be intercepted by hacker (symmetric)
      • managing digital certificates can become complex and time consuming

Symmetric Encryption​

  • only private key
    • used to both encrypt and decrypt the messages
  • shorter amount of time
  • less processing power to encrypt
    • and also decrypt the message
  • less complex & fast & less secure

Asymmetric Encryption​

  • often reffered to as public key encryption
  • two keys are used
    • no need to transfer one key
    • so, more secure
  • public key to encrypt data
    • public key is visible to everyone
    • is shared publicly
  • matching private key to decrypt the data
    • is kept secret
  • anyone with a public key can encrypt information, and can be ready by
  • it is not possible to deduce/re-calculate private key from the public key
  • more complex & fast & more secure

Malware​

  • industrial espionage

    • downloading without realizing
      • when clicked on adware
    • trojan / spyware can be used
    • malware gains access to environment variables & database contents
    • data collected is sent back to hacker
    • used to exploit weaknesse in software to gain access,
      • eg: priviliage escalation
    • targetted social engineering attacks (eg: phishihg, etc...)
      • and installs spyware
    • has to be run/executed by target person

  • how to stay safe?

    • follow anti-malware policies
    • use anti-virus / anti-malware
      • detects and quarantees malware
      • asks user to delete or keep
    • keep anti virus upto date
    • use firewall to filter incoming traffic
      • and outgoing traffic
        • unknown ports
        • used by backdoors / reverse shells
    • use anti-spyware softwrae
    • use spam filter tools in email
    • only download software from trusted source
    • report unknown behaviour to IT helpdesk engineers
    • disconnect from network soon

  • consequences if hacked (company)

    • computer networks can be wrecked
    • will disturb bussiness
      • so, income loss
    • steal organization's data
      • may ask for ransom if not will share (ransomware)
      • or will just share
      • giving advantage to other companies
      • will result in lawsuits
    • infected devices has to be disconnected from the network ASAP
      • to prevent spreading to other networks if its a worm
    • will have to pay more
      • for IT staff
      • to clean / di-infect the computers
    • will slow the computers down
    • stealers may steal user activity (including browser session cookies)
      • can log in without passwords, using session cookie
      • to cause harm to the computer
    • rootkits allow computer to be taken over (and commit illegal acts)

Rootkits​

  • gives admin access to computer
  • hiding to the user
  • 'root' refers to admin account in linux
  • 'kit' refers to software components used to impletent that tool
  • can be installed in many ways
  • allows attacker to maintain command and control
  • controller can remotely execute files
  • controller can change system configurations
  • can access log files and spy on computer's usage
  • hard to detect, runs at system level
  • difficult to get rid of
  • can hide illegal files on computer
  • designed to have anti-malware techniques

Malicious Bots​

  • to automate tasks
  • used to gather information (web crawlers)
  • also used to interact dynamicllay with websites
  • self-propagating malware to infect a host and connect back to central server
  • attackers can launch remote-control type flodding attacks
  • can launch DDOS attacks
  • can infect immediately

Ransomware​

  • encrypts data and thratens to share unless ransom is paid
  • user files become decipherable
  • enceryption key is given only if ransom is given
  • iniltrates as a trojan or a worm
  • from websites or infected email attatchments
  • some allows the use of computer, but prevents opening files by encrypting them

Trojan Horse​

  • ditinctive features
    • disguises authentic software
    • do not affect to infect other files
    • do not self replicate themselves
    • provides backdoor from computer to attacker's C2 server

Worm​

  • ditinctive features
    • standawlone malware
    • replicates itself
    • find vulnerabilities in networks (eg: samba)
      • copies sent to other computers
    • slows downt the network

Spyware​

  • ditinctive features
    • collects user activity
      • web browser activity
      • messaging activity
      • browser session cookies
      • saved bank card information
    • passwords sent to hacker (without user's knowledge)
    • keylogger logs keystrokes and sends to attacker
    • does not usually replicate like a worm
  • how hackers can abuse these data?
    • can sell information to criminals
    • can impersonate
    • can trick banks into asking new card PIN or transferring (withdraw) large amounts of money
    • can buy extra credit cards

Adware​

  • distinctive features
    • Automatically generates advertisements in order to gain revenue for its
    • author
    • Advertisements may appear in the user interface/screen shown to the user
    • by the software
    • Examines which intemet sites visited and presents advertising according to
    • the types of goods/services featured on these/usually the type of
    • goods/adverts the user is interested in.

Social Engineering​

Phishing​

  • meaning
    • sending an email to lure personal information from victims
    • may include URL to website
      • looks like bank, but a fake website
      • asks customer to enter bank details
    • easily grabs attention
      • eg: We confirm that you have signed up to our service and will be charged 50$ per month.
    • email may ask customer to reply
      • and enter their personal information
  • how to be safe?
    • dont trust emails sent from unrecognized senders
    • only contact the bank physically
    • dont open links from unknown senders
    • dont send personal information over email
    • protect computer using firewall
    • keep anti-malware tools upto-date
    • look for grammartical errors

Smishing​

  • meaning
    • sending a text message to lure personal information from victims
    • text message may include
      • a URL
        • looks like a bank's website (but its fake)
        • asks for personal information
      • a phone number
        • that connects to a scammer asking for bank details
      • message usually grabs immediate attention
  • how to be safe?
    • avoid links in text messages
    • dont send texts with personal info
    • if a message is from bank, visit the bank physically and confirm
    • neglect everything thats like:
      • "call this number or we will cancel your credit card, etc..."

Vishing​

  • meaning
    • victim recieves phone call
      • claims to be from a bank
      • and tells we detected fradulent activities
      • robocall, will ask customer to call the fake bank
    • scammer answers fake bank
    • scammer tricks the victim to send money to scammer's bank account
    • dont give them any codes recieved by SMS or OTP codes
      • a legitamate bank will never ask for it via call
  • how to be safe?
    • dont give sensitive information from phone
    • dont answer calls from unknown callers
    • log into your back and check for suspicous activity
    • register your phone number with "national do not call list"
    • dont call numbers sent in voicemail
    • check background information on phone numbers

Pharming​

  • involves creating a fake website that looks like the actual website
  • meaning
    • installs malware to computer
    • when user tries to access bank's website
    • will redirect to fake website that looks real
      • (redirects genuine website's traffic to own website)
      • victim enters personal information to fake site
      • it will notify the attacker
  • meaning (complex)
    • create and host fake website that looks like legit bank's site
    • fools the user into thinking they are in the correct site
    • malware spreaded by hacker
      • adds entries to host file
    • OR, in public wifi's
      • DNS settings are changed to point to fake IP for domain
    • so, when user accessed original site (domain), traffic is forwarded to fake site
    • site asks to enter fake information
    • hacker uses stolen information to log into user's bank account
    • and withdraw money
  • how to stay safe?
    • use upto-date anti-virus to prevent downloading malware
    • firewalls to prevent malware
    • use trusated DNS servers
    • use an upto-date trusted browser, eg: Google Chrome, Firefox
    • use trusted ISP
    • check digital certificate to ensure its an original website
    • be suspicous if the site has grammar mistakes
    • dont use public wifi systems

General Online Safety​

  • only use websites recommneded by teachers
  • think twice before opening an email
  • should not now how to block and report unwated users from social media styles
  • dont use real name of games like sites

Other (Move)​

Software (for software and hardware)​

  • blogging, which software can be used:

    • Using word processing it is easier to edit documents ready for inclusion in the
    • website compared to text editors, spreadsheets and databases
    • Using word processing it is easier to format documents ready for inclusion in
    • the website compared to text editors, spreadsheets and databases
    • Using word processing it is more difficult to enter statistics and manipulate
    • these compared to spreadsheets and databases
    • Easier to calculate statistics with a spreadsheet than using database software
    • Can produce charts to show sales growth with a spreadsheet easier than using
    • a database
    • Databases could be used to store and process sales figures easier than a
    • spreadsheet
    • Easier to query a database than using a spreadsheet
    • Easier to produce reports with a database than a spreadsheet
    • With a text editor formatting is not lost when convening to HTML
    • Using web authoring package is easier to produce a blog than using text
    • editor...
    • ...easier to use than text editor as functions are provided.

  • antivirus

    • description
      • Scans the computer to make sure it is not infected with a virus/to find
      • viruses
      • Compares with existing viruses/detects changes in behaviour of files
      • It may quarantine the infected programs
      • It will ask the user whether or not they want to delete the infected programs
      • (Does background scans of downloads and attachments for viruses) and
      • informs the user if anything found.
    • advantages
      • protects from malware
      • prevents data being stolen + deleted by malware
      • can prevent passwords being changed
      • can filter spam from mailbox
      • users can select how regularly to scan automatically in background
      • can select which drives/folders to scan
      • quarantines any infected files
        • and awaits user confirmation to delete it
    • disadvantages
      • cost of purchase / license
      • should be purchased anually
      • need to update a lot
        • since new virus signatures are being added almost daily
      • can detect virus stored in DB (signature based)
      • can detect viruses based on behaviour (behaviour based)
      • can slow down the computer
      • does not give 100% coverage
      • can give false positives
        • specially if you are a programmer
        • eg: web server opening a port locallt in your system to server the web files / API
      • takes up storage and memmory

  • backup software

    • Creates (additional exact) copies of files, databases hard disks or network
    • servers
    • Use these copies to restore the original contents in the event of data loss
    • Asks user to enter type of backup
    • Asks if you wish to restore the backup
    • Asks if you wish to verify the backup
    • Asks when backup is to take place/frequency of backups.

  • disk defragmentation software

    • Rearranging files stored on a disk
    • Causes data to occupy contiguous storage locations
    • Physically organises the contents of the mass storage device used to store
    • files
    • Organises data into the smallest number of contiguous regions (fragments)
    • Attempts to create larger regions of free space.

Digital Divide​

  • in schools
    • BYOD widens digital divide
    • widens digital divide
      • Students whose families can afford the devices have an unfair advantage
      • Teachers find it difficult to manage learning activities when they have to
      • support multiple platforms and device types
      • Some activities and applications may only be compatible with certain devices
      • The gap widens as underprivileged students lack access to high performance
      • computers at home
      • Underprivileged students do not have intemet access at home so they do not
      • leam the same things putting them at a distinct disadvantage.
    • rectify digital divide
      • Teachers could be given time to train on and understand the platforms they are
      • using
      • Teachers could have to learn how to integrate them into a class of students
      • who may not have access to the internet or mobile devices at home
      • Schools need to have different versions of software that can be used on all
      • devices
      • Libraries and schools should offer technology training for parents
      • A fund for the purchase or subsidy to purchase machines for poor children
      • A stock of spare machines kept in school in case students do not have
      • machines
      • A list of software could be issued to staff which runs across all platforms.