Networks
describe week passwords?
-A weak password is short, common, or something that could be quickly guessed such as words in the dictionary, proper names, words based on the user name or common variations on these themes. -allow easy access to data in a brute force attack
why is captcha not as effective anymore?
-Image recognition software and artificial intelligence is developing -machines are becoming more capable of passing these tests
describe star topology?
-all devices are connected to centre -all devices connected to central switch or server that controls the network -central switch allows many devices to access the server simultaneously -can be wired or wireless
describe bus topology?
-all devices connected to a single cable -use single backbone cable called a bus to connect all devices -two terminators placed at end pf the bus to stop data reflecting back along the bus -without terminators reflected signals would cause interference and make network unusualble
Describe viruses
-attach to certain files -users spread them by copying infected files and activate them by opening infected files -has ability to replicate and spread -attaches itself to a legitimate program -can corrupt or destroy data
Why is packet switching efficient use of the network ?
-because there are so many possible routes that each packet can take -packets can reach their receiving device quickly even if there's heavy traffic
describe adware?
-can cause pop ups and can't be closed
describe CAT 5 and CAT 6
-common types of ethernet cable -contain pairs of copper wires twisted together to reduce internal interference -cheaper than fibre optic -have a decent bandwidth -commonly used in homes and offices to connect devices on a LAN
describe user access levels?
-control which parts of the network different groups of users can access -they limit number of people with access to important data -help prevent attacks within organisation
what are the benefits of wireless networks?
-conveniant- get your device automatically to connect to the network -move around while connected to network -cheaper -better for environment as dont need wires -easy to add more users -dont need to install wires or any complex setup
describe a LAN?
-covers small geographical area located on a single site -all hardware owned by organisation that uses it -can be wired or wireless -buisinesses, schools and universities use them -homes have a lan connected to various devices
Describe phishing.
-criminals send emails or texts claiming to be from well known businesses -the emails often lead to a fake website just like pharming -emails often sent to thousands of people
cons of bus topology?
-data collisions are common, data has to be resent if collided which slows it down -more devices added the more likely colliosn are -unsuitable for large networks -to avoid Collins devices ,use wait for the bus to be available which slows it down -if bus cable gets broken it splits the network into separate parts- these dont have terminators at both ends so there will be reflected signals that can shut down entire network.
what are the types of action malware include?
-deleting or modifying files -locking files -displayong unwanted adverts -monitoring the user -altering permisions eg ransomware
describe anti-malware software?
-designed to find and stop malware from damaging an organisations network and the devices on it
describe trojan malware?
-disguiseed as legitimate software -dont replicate themselves -user installs them without realising they have hidden purpose -once installed they will infect other files
what can reduce signal strength of wireless networks?
-distance from WAP -interferance from other networks -physical obstructions
what are the five ways to keep networks secure from hackers?
-encryption -anti-malware software -user access levels -automatic software updates -MAC address filtering
how can you reduce pharming
-ensure anti-malware is up to date -internet browsers can use web filters to prevent users from accessing these fake sites
What do firewalls do?
-examine all data entering and leaving a network and block any potential threats -companies use firewalls to prevent unauthorised access
what are the drawbacks of networking?
-expensive to set up, often need lots of extra hardware -vulnerable to hacking -malware can easily spread between networked computers -some are dependent on one or more servers, if those servers go down it can be very disruptive for people trying to use the network -large networks are difficult to manage -may require employing a specialist to maintain them
what do protocols cover?
-how communication between two devices should start and end -how the data should be organised -what the devices should do if data goes missing
what does HTTP stand for and what is it used for
-hyper text transfer protocol -used by web browsers to access websites and communicate with web servers
what are the pros of star topology?
-if device fails or cable is disconnected the rest of network is unaffected -simple to move and add more devices as each device is connected to switch with separate cable -better performance, data goes straight to central device so all devices can transmit data at the same time -fewer data collisions
what are the cons of star topology?
-in wired, every device needs a cable to connect to central switch or server -expensive -if problem with switch or server whole network is affected -maximum number of possible connections is determined by switch so you might have to buy new one
what are the drawbacks of wireless networks
-less secure: access points visible to all devices -limit to how far it can reach -lower bandwidth and less reliable
what's a hotspot?
-locations where you can connect to a WAP
describe MAC address filtering?
-makes sure only people on network are trusted users -checks unique identification of each device that tries to connect to the network and only lets allowed devices to join network
what should a strong password have?
-many charcters -use a combination of letters, number and symbols -chnaged regularly
how can you protect against phishing?
-many email programs, browsers and firewalls have anti-phishing features that will reduce number of phishing emails received -giveaways: poor grammar, asked to follow links, not personal
describe outdated software?
-means there are vulnerabilities in a program or code. -Users can also be responsible for their unpatched software if they refuse to check for and perform regular updates.
describe two factor authentication
-method where a computer user is granted access only after successfully presenting two or more pieces of evidence to an authentication mechanism
pros of bus topology?
-network is unaffected if device fails -not dependent on single central switch -cheap to set up -less wiring and hardware you need which is cheaper than switches both to buy and maintain
describe a WAN
-network that connects LANs -connects LANs in different geographical locations -organisations hire infrastructure because WAN is much more expensive to set up than LAN -connected using telephone lines, satellite links or radio links -internet is one big WAN
how can you protect against trojan?
-only downloading software from reputable sources
what is penetration testing?
-organisations employ specialist to simulate potential attacks to their system -used to identify possible weaknesses in their cyber security -results can be used to fix vulnerabilities
what are the 4 forms of social engineering?
-phishing -blagging -pharming -shouldering
describe an NIC?
-piece of hardware inside a device that allows it to connect to networks -exist for both wired and wireless connections
describe a USB dongle?
-plugged into computers to allow them to connect wirelessly to the internet
Describe spyware
-secretly tracks actions like key presses and sends info to hackers who might be able to work out passwords and bank details
describe worms?
-self-replicate without users help -spread very quickly -exploit weaknesses in system
what are the benefits of networking computers?
-sharing files is easier, access same files, work on them at same time and copy files between machines -share same hardware between multiple devices -install and update software on all computers at once -can communicate across a network cheaply and easily -user accounts can be stored centrally so users can log in from any device on the network
why is bluetooth used for PANs?
-signal is quite strong -but has very short range -ideal for connecting devices in same room
Describe the coaxial cable.
-single copper wire surrounded by a plastic layer for insulation and a metallic mesh which provides shielding from outside interferance -very cheap -low bandwidth
What is malware?
-software that has malicious intent and can harm devices -code designed to cause harm or gain unauthorised access to a computer system -often installed on device without knowledge or consent of owner
what is data sent between networks split into?
-split into equal sized packets
what are four topologies?
-star -bus -ring -mesh
what are five ways to prevent unauthorised access
-stronge passwords -biometrics -two factor authentication -email confirmation -CAPTCHA
Describe fibre optic cables
-transmit data as light -high performance -expensive cables -dont suffer interference -transmit data over very large distances at high bandwidth without loss of signal quality
What are routers used for?
-transmit data between different networks -most commonly used to connect to Internet
what are the 5 types of malware?
-trojan -virus -adware -spyware -ransomware
how do you prevent spyware?
-use antivirus and anti-spyware software -stay updated and have security patches -set your browser and privacy levels high -dont click on ads
describe biometrics
-use scanners to identify people by a unique body part eg retina, fingerprint -smartphones use fingerprint scanners or Face ID to prevent unauthorised access -usually quite secure and convenient for user but are often more expensive to implement as they require special hardware
how can you prevent blagging?
-use security measures can't can't be given away eg biometrics -never give details over phone
describe email confirmation
-used by most web services that require account registration to confirm that the email address belongs to the person registering -stop people using fake emails -people can just sign up for new email address whenever they want however so less effective
what are switches used for?
-used to connect t devices on a LAN
describe automatic software updates?
-used to patch any identified security holes in a piece of software -software that is unpatched or outdated could be more easily exploited by hackers, malware and viruses
how is pharming often carried out?
-using malware that automatically redirects people from legitimate sites to fake ones
what are four other threats?
-weak and default passwords -misconfigured access rights -removeable media -unpatched/outdated software
Describe encryption
-when data is translated into a code which only someone with the correct key can access -unauthorised users cannot access it -essential for sending data over a network securly
describe blagging?
-when someone makes up a story or pretends to be someone they're not to persuade the victim to share information or do things they wouldn't normally do eg fake friend emails or phoning pretending to be someone important -they use pressure
describe pharming?
-where the user is directed to fake version of a website -designed to look like the real thing -aim that the user won't notice the difference -when user puts information into website they're hading it over to criminals who can access their genuine accounts
what are the three ways malware can spread between devices?
-worms -viruses -trojans
What is a client/server network?
A centrally administered server (or servers) that manage shared resources for multiple clients. The server has greater authority than the clients (typically desktop or laptop workstations).
what is a network policy?
A set of rules and procedures the organisation will follow to ensure their network is protected against any possible security threats
What is a protocol?
A set of rules for how devices communicate and how data is transmitted across a network
what is social engineering
A way of gaining sensitive information or illegal access to networks by influencing people.
what does HTTPS stand for and what is it used for
HTTP secure -a more secure version of HTTP -encrypts all information sent and recieved
Describe a mesh topology
In a mesh network topology there is no central connection point. Instead, each node is connected to at least one other node and usually to more than one. Each node is capable of sending messages to and receiving messages from other nodes. The nodes act as relays, passing on a message towards its final destination.
What does IP stand for?
Internet Protocol
what is a LAN?
Local Area Network
what is an NIC?
Network Interface Card
what is patching
Patching is the process of updating software to fix a problem or add a new feature.
what is a PAN?
Personal Area Network
Cons of Ring Topology
The disadvantage is that if the one cable breaks, all the computers will not work.
What are gateways?
These allow two different networks to speak to one another by translating data.
What are bridges?
These are used to join - or bridge - two LANs together to form one larger network.
Pros of Ring Topology
This is fast because, unlike with a bus network, all data travels one way down the cable.
what is a protocol example of layer 1
WIFI, ethernet
what are local wireless networks called?
WLAN -or wifi
Describe a ring topology?
Where data passes through each node, carried in data units called tokens. Traffic is one way which prevents collisions.
what is a WAN?
Wide Area Network
what is a WAP
Wireless Access Point -a switch that allows devices to connect wirelessly
What is an extranet?
a private, corporate computer network that links company departments, employees, and databases to suppliers, customers, and others outside the organization
What is an Intranet?
an Internet-based network used within the boundaries of an organization. It is a private network that may or may not be connected to the public Internet.
What is a peer-to-peer network?
any network without a central file server and in which all computers in the network have access to the public files located on all other workstations
describe a PAN
connect devices over very short range -normally cantered round single user -used to transmit between mobile/wearable devices -use wireless technology eg bluetooth to connect devices -usually don't require additional hardware -you can create PAN on the move
what should all data be on wifi networks?
encrypted
What does FTP stand for and what is it used for?
file transfer protocol -used to access, edit and move files between devices on a network
what's an example of anti-malware software?
firewalls
Cons of Mesh Topology
full mesh network topologies can be impractical to set up because of the high number of connections needed having many connections means that a lot of maintenance is required a large part of the network may be redundant if there are better routes to connect nodes, making some connections unnecessary
what does IMAP stand for and what is it used for
internet message access protocol -used to retrieve emails from a server
what are network protocols divided into?
layers
what do networks require?
lots of hardware. Cables, Switches, Router, Firewall, Servers, Clients, Printers, scanners
What is malware short for?
malicious software
Pros of a mesh topology
messages can be received more quickly if the route to the intended recipient is short messages should always get through as they have many possible routes on which to travel multiple connections mean - in theory - that no node should be isolated multiple connections mean each node can transmit to and receive from more than one node at the same time new nodes can be added without interruption or interfering with other nodes
Uses of Mesh Networks
military organisations often use mesh network topologies to avoid breakdowns in communication cities are increasingly using wireless mesh network topologies to help monitor traffic flow and sewage treatment, and to help control street lighting emergency services, such as police and fire services, also use wireless mesh network topologies to ensure that communication is reliable some utility companies who provide gas and electric use mesh network topologies to allow smart meters to send readings automatically
What is IP responsible for?
packet switching
what do wireless networks use to transmit data?
radio waves
what does SMTP stand for and what is it used for
simple mail transfer protocol -used to send emails -used to transfer emails between servers
how to prevent adware?
stay updated, Scan your system
What is cyber security?
the techniques of protecting computers, networks, programs and data from unauthorized access or attacks
what is the purpose of captcha?
to prevent programs from automatically doing certain things like creating user accounts on a website
What are IP addresses?
unique numbers assigned to every device connected to an IP network
describe shouldering
watching and observing a persons activity typically over their shoulder -eg watching someone at cash machine
