C HAPTER 5 General Computer Topics

5.1 Computer Crimes Computer crime refers to any crime that involves a computer and a network. Net crime refers to criminal exploitation of the Internet. Computer crime encompasses a broad range of activities. Generally, however, it may be divided into two categories: (1) Crimes that target computers directly; (2) Crimes facilitated by computer networks or devices..

5.1 Computer Crimes Crimes that primarily target computer networks or devices include: A computer virus is a computer program that can replicate itself and spread from one computer to another. Denial-of-service attacks: In computing, a denial- of-service attack (DoS attack) or distributed denial-of-service attack (DDoS attack) is an attempt to make a machine or network resource unavailable to its intended users.

5.1 Computer Crimes Malware (malicious code) : Malware, short for malicious software, is software used or created to disrupt computer operation, gather sensitive information, or gain access to private computer systems. It can appear in the form of code, scripts, active content, and other software. Spam, or the unsolicited sending of bulk for commercial purposes, is unlawful in some jurisdictions. Computer fraud is any dishonest misrepresentation of fact intended to let another to do or refrain from doing something which causes loss.

5.2 Computer Viruses It is an application program designed and written to destroy other programs. It has the ability to link itself to other programs and copy itself (it looks as if it repeats itself). Examples: Monkes, ABC, Crabs and CIH Viruses A virus program is man-made and it infects programs, documents, databases and more. It can hide and reproduce. It can lay dormant (inactive) and then activate

5.2.1 Viruses  A variety of highly contagious “viruses” can spread from computer to computer.  It can infect programs and databases.  It can also hide and duplicates itself within legitimate programs.  These program viruses can reside on and pass between magnetic disks.  Most people who write and circulate virus programs fall into one of the following two groups:  the first uses viruses to show off for their peers  the other which is far more dangerous group, creates viruses with malicious intent.

5.2.1 Viruses There are three main computer viruses:  The first is Macro viruses which is written into the program macro and shuts down functions.  The second is Worm, that makes copies of itself and interfere with normal operations.  The third virus is Trojan horse. The three primary sources of computer viruses are: – The Internet :Via downloads and exchanges – Secondary storage: Exchanging disks – Computer networks : Can spread from one network to another How do you know if you have a virus? The answer comes when you notice one of the following symptoms.  Lack of storage capability  Decrease in the speed of executing programs  Unexpected error messages  Halting the system

5.2.2 Virus Protection The software package distributed with new PCs always includes an antiviral program. The best way to cope with viruses is to recognize their existence and use an antiviral or antivirus program. Some tips that will help minimize your vulnerability to viruses: Delete s from unknown or suspicious, untrustworthy (unreliable) sources. Never open a file attached to an unless you know what it is. Download files from the Internet only from legitimate and reputable sources. Update your antivirus software at least every two weeks. Backup your files periodically.

5.3 Computer Ethics You shall not use a computer to harm other people. You shall not snoop around in other people's computer files. You shall not use a computer to steal. You shall not use other people's computer resources without authorization or proper compensation. You shall always use a computer in ways that show consideration and respect for your fellow humans.