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& myCBSEguide.com, , A Complete guide for CBSE students, , CBSE Revision Notes, Class-11 Computer Science (New Syllabus), Unit 4: Society, Law and Ethics (SLE-1) - Cyber safety, , Safely Accessing Websites, , While accessing any website we should always be aware it’s safe and it does not contain any, harmful content in like virus and other malicious things always try to access websites which, has https:// in it rather http:// here “s” means secure. Let’s see some of the possible threats, which you might get while accessing websites., , Adware: Adware, or advertising-supported software, is software that generates revenue for, its developer by automatically generating online advertisements in the user interface of the, software or on a screen presented to the user during the installation process. The software, may generate two types of revenue: one is for the display of the advertisement and another, on a "pay-per-click" basis, if the user clicks on the advertisement. The software may, implement advertisements in a variety of ways, including a static box display, a banner, display, full screen, a video, pop-up ad or in some other form., , Some software developers offer their software free of charge, and rely on revenue from, advertising to recoup their expenses and generate income. Some also offer a version of the, software at a fee without advertising., , The software's functions may be designed to analyse the user's location and which Internet, sites the user visits and to present advertising pertinent to the types of goods or services, featured there. The term is sometimes used to refer to software that displays unwanted, advertisements known as malware., , Malware: Malware, or malicious software, is any program or file that is harmful to a, computer user. Malware includes computer viruses, worms, Trojan horses and spyware., These malicious programs can perform a variety of functions, including stealing, encrypting, or deleting sensitive data, altering or hijacking core computing functions and monitoring, users’ computer activity without their permission., , Programs officially supplied by companies can be considered malware if they secretly act, against the interests of the computer user. For example, company ABC sold the rootkit, which, contained a Trojan horse embedded into CDs that silently installed and concealed itself on, , Material downloaded from myCBSEguide.com. 1/3

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& myCBSEguide.com, , A Complete guide for CBSE students, , purchasers’ computers with the intention of preventing illicit copying. It also reported on, users’ listening habits, and unintentionally created vulnerabilities that were then exploited, by unrelated malware., , One strategy for protecting against malware is to prevent the malware software from gaining, access to the target computer. For this reason, antivirus software, firewalls and other, strategies are used to help protect against the introduction of malware, in addition to, , checking for the presence of malware and malicious activity and recovering from attacks., , Virus: A computer virus is a type of malicious code or program written to alter the way a, computer operates and that is designed to spread from one computer to another. A virus, operates by inserting or attaching itself to a legitimate program or document that supports, macros in order to execute its code. In the process a virus has the potential to cause, unexpected or damaging effects, such as harming the system software by corrupting or, destroying data. Once a virus has successfully attached to a program, file, or document, the, virus will lie dormant until circumstances cause the computer or device to execute its code., In order for a virus to infect your computer, you have to run the infected program, which in, turn causes the virus code to be executed. This means that a virus can remain dormant on, your computer, without showing major sings or symptoms. However, once the virus infects, your computer, the virus can infect other computers on the same network. Stealing, passwords or data, logging keystrokes, corrupting files, spamming your email contacts, and, even taking over your machine are just some of the devastating and irritating things a virus, can do., , Trojans: In computing, a Trojan horse is a program that appears harmless, but is, in fact,, malicious. Unexpected changes to computer settings and unusual activity, even when the, computer should be idle, are strong indications that a Trojan is residing on a computer., A Trojan horse may also be referred to as a Trojan horse virus, but that is technically, incorrect. Unlike a computer virus, a Trojan horse is not able to replicate itself, nor can it, propagate without an end user's assistance. This is why attackers must use social, engineering tactics to trick the end user into executing the Trojan. Typically,, , the malware programming is hidden in an innocent-looking email attachment or free, download. When the user clicks on the email attachment or downloads the free program, the, malware that is hidden inside is transferred to the user's computing device. Once inside,, the malicious code can execute whatever task the attacker designed it to carry out., , Material downloaded from myCBSEguide.com. 2/3

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& myCBSEguide.com, , A Complete guide for CBSE students, , Because the user is often unaware that a Trojan horse has been installed, the computing, device's security depends upon antimalware software that can recognize malicious code,, isolate it and remove it. To avoid being infected by Trojan malware, users should keep their, antivirus software up to date and never click on links from untrusted sources or download, files from unknown senders., , Material downloaded from myCBSEguide.com. 3/3