4.4 THE PROTECTION OF COMPUTERS 98 Give a definition of the word hacking . The term Trojan is derived from the Ancient Greek story of the deceptive Trojan horse that led to the fall of the city of Troy. ONLINE RESOURCES Mobile malware COMPUTER THREATS A computer threat is a negative action or event that can compromise it. Threats can lead to cyber attacks or data being stolen, lost or modified by others. A threat can be either intentional, as in the case of hacking , or accidental, as in the case of computer malfunctioning or a natural disaster that seriously damages the system. Most intentional threats can be classified as follows. Malware The term malware (short for malicious software ) refers to any intrusive software or code created to damage or disable computers or mobile devices. Its most common forms are: Viruses, which attach to another program and, when executed by the unaware user, replicate themselves by modifying computer programs and infecting them with their own code; Adware, which is unwanted software designed to make adverts pop up on the screen most often within a web browser, which slows down the system; Spyware, which secretly keeps track of the computer user s activities without permission; Worms, which are similar to viruses because they self-replicate, but which, unlike viruses, can spread across systems on their own without any action from the user; denial: negazione, rifiuto to flood: inondare fraud: frode fund: fondo to overwhelm: travolgere ransom: riscatto unaware: ignaro Trojans , which, once on the computer system, allow attackers to gain unauthorised access to the computer in order to steal financial information or install other forms of malware; Ransomware, which locks the user out of the device and/or encrypts files, and forces them to pay a ransom to regain access. Crimeware Crimeware is a general term referring to a set of programs used to commit illegal activities online, such as stealing personal identities, money, sensitive data or proprietary information. An example of crimeware action is when a user s financial accounts are accessed with the purpose of taking funds from them or completing unauthorised transactions. Crimeware uses different types of malware so it may be a virus, spyware or other piece of software that can be used to commit fraud. Network threats A network threat or attack is aimed at gaining unauthorised access to an organisation s network to steal data or perform other malicious activity. Network attacks can be: passive, when attackers gain access to a network without making any change to the data; or active, when attackers gain access and modify data, either deleting or encrypting it. DDoS (Distributed Denial of Service) is one of the most common network threats that cybercriminals use to make an online service or network resource unavailable to its users on the Internet by flooding it with thousands or millions of superfluous requests, overwhelming the system. 216 TelecoMMUNicaTioNs aND NeTWorKs Elettronica-Informatica.indb 216 25/01/24 16:09