1.4 Network Security

malicious software, created with the intent to: Cause damage to computer systems or Steal data

Vulnerabilities can be caused by: Human weakness Software issues Code quality

malware in the form of a program that attaches itself to another file and can replicate itself when the file is executed. DEFENCE: Antivirus and anti-malware software Don’t click on links from unknown sources

malware that is able to replicate itself and does not need to use another file as a vector. DEFENCE: Antivirus and anti-malware software Don’t click on links from unknown sources

a piece of malware that is hidden inside another file in a computer system A trojan is a piece of software that appears to be legitimate (such as a game), to trick the user into executing it. DEFENCE: Antivirus and anti-malware software Don’t click on links from unknown sources

Remote Access Trojan The main objective of a trojan is to steal confidential information or inflict damage. A type of trojan is a remote access trojan (RAT). A computer with a RAT may become a bot under the remote control of a hacker. DEFENCE: Antivirus and anti-malware software Don’t click on links from unknown sources

When the hacker controls many computers, the computers form a botnet. A botnet (robot network) is a network of computers that are under the control of a single operator who can instruct all of the computers to do something at the same time. This could be to send out spam emails or perform a distributed denial of service (DDos) attack on a chosen target. DEFENCE: Antivirus and anti-malware software Don’t click on links from unknown sources

a form of malware that captures data from a computing device and transmits it without the user’s knowledge. DEFENCE: Anti-malware software

Spyware. A keylogger can keep a record of all keys pressed, meaning that usernames and passwords are recorded and transmitted back to the malicious software author. DEFENCE: Anti-malware software

a form of malware that locks a computer or encrypts files, and therefore prevents a user from accessing their data. The attacker will demand a fee (ransom) is paid before they release the files, although there is no guarantee that the user will get their files back, even after they have paid the ransom. DEFENCE: Anti-malware software

techniques used to trick users into giving away personal information by psychological manipulation It is different to other cyber crimes because it involves humans trying to trick or manipulate other humans DEFENCE: Security training

an attack in which the victim receives a message disguised to look like it has come from a reputable source (for example, a bank), in order to trick them into giving up personal information. DEFENCE: Security training Network policy Firewall User awareness of phishing ‘clues’

Spear phishing is a more sophisticated version of the scam, where a fraudulent message is sent to a specific person and often includes personal details in order to appear legitimate. For example, rather than sending phishing emails to a whole company, a spear phishing attack might just aim at the finance director and be more personalised DEFENCE: Security training Network policy Firewall User awareness of phishing ‘clues’

deceiving users by sending them to a fake website that the user believes is the real one, with the intention of tricking them into submitting personal information. DEFENCE: Security training

A more sophisticated method of pharming, known as DNS poisoning involves hacking a DNS (the database that allows your browser to find the website that you are visiting). When the victim enters a correct web address of the site they wish to visit into their browser, they visit a website controlled by the attacker, rather than the legitimate website.

an attack in which the attacker invents a scenario in order to convince the victim to give them personal information or money. DEFENCE: Security training

a type of social engineering attack design to steal a victim’s password or other sensitive information by using close visual observation. DEFENCE: Security training Concealing your password or pin entry User access levels User awareness

someone who deliberately gains, or attempts to gain, unauthorised access to a computer system with the intent to cause damage or steal data

expert in computer security who attempts to gain access to a computer system in order to find vulnerabilities. If an ethical hacker is working with the permission of the network owner, this activity can be classed as penetration testing. However, if they are working without permission, the activity is illegal.

Under the Computer Misuse Act, there are heavy penalties, including prison sentences, for anyone who makes an attempt to access a system without authorisation.

where a hacker hacks the connection between two people or systems and intercepts the data they are passing to each other. The hacker may take the data or may alter it so that the recipient receives data that has been tampered with in some way. The users will be unaware that the data has been intercepted. This kind of attack can be orchestrated by a malicious person setting up a free unencrypted Wi-Fi hotspot. Any data that is passed across the network can be readily intercepted.

is a computer that provides services to client computers. An example of a server is a web server that provides webpages. Servers are usually set up to run 24 hours a day, 7 days a week, constantly listening for requests for their services.

Servers are configured to be able to cope with a certain volume of traffic. In a denial-of-service attack, a server will be bombarded with requests at a level that it cannot cope with. Anyone else who is trying to access the server will find that their request cannot be processed, therefore causing a denial of service. DEFENCE: Firewall

Distributed Denial of Service. A malicious attempt to overwhelm a server by bombarding it with requests. In a distributed attack, the requests come from a large number of distributed computer systems, typically a botnet. DEFENCE: Firewall