This document discusses different types of malware such as viruses, worms, and Trojan horses. It explains that viruses can copy themselves without permission and attach to other programs or files. Worms are self-replicating programs that use networks to send copies of themselves to other computers without user intervention. Trojan horses perform desirable functions but also have hidden and unwanted functions like leaking private information.

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2. A kind of software programs produced by unknown people and harmful to the computers Some varieties of these software are the Viruses , Worms and Trojan horses 02/28/12

3. The term “Virus" is often used in common to describe all kinds of malware (malicious software) including adware and spyware programs that do not have the reproductive ability. 02/28/12

4. Trojan horse perform a desirable function for the user in addition to the expected function Leaks information Usually does not reproduce 02/28/12

5. A worm is a self replicating malware computer program, which uses a computer network to send copies of itself to other computers and it may do so without any user intervention. It does not need to attach itself to an existing program. 02/28/12

6. Sometimes display unwanted messages Some tend to destroy programs or data Clog computer memory and hence sometimes result in system crashes Format hard disks, Damage programs, Delete files 02/28/12 Viruses

7. Simply replicate themselves Presents text, video, or audio messages making the user know their presence Bug-ridden, and these bugs may lead to system crashes and data loss 02/28/12

8. A viruses can copy itself and infect a computer without permission or knowledge of the user attaches itself to other software programs or data files 02/28/12

9. Spreads from computer to computer when the host is taken to the uninfected computer over a network such as over the Internet or carrying it on a removable medium - a floppy disk, CD, or USB drive 02/28/12

10. Many viruses are existed in the Internet today and new ones are discovered every day. spread via downloaded software and data files, and email attachments etc. 02/28/12

11. Some old viruses are installed themselves into the disk boot sector runs when the user boot the computer from the disk 02/28/12

12. Some viruses spread through instant messaging A virus, in an infected machine, may send a web address link as a message to other contacting machines Thinking the link is from a friend (a trusted source), the recipient may sometimes follow the link to the website. 02/28/12

13. ANSI COBOL C/C++ Pascal VBA Unix Shell Scripts Javascript 02/28/12

14. Unlike biological viruses, computer viruses do not simply evolve by themselves deliberately created by programmers, or by people who use virus creation software 02/28/12

15. Viruses are written as research projects, pranks, vandalism, to attack the products of specific companies, to distribute political messages, and financial gain from identity theft, spyware, and cryptoviral extortion. 02/28/12

16. Some virus writers consider their creations to be works of art See virus writing as a creative hobby 02/28/12 Releasing computer viruses is a crime in most jurisdictions

17. File infector virus Infect program files Boot sector virus Infect the system area of a disk Master boot record virus infect disks in the same manner as boot sector viruses. The difference between these two virus types is where the viral code is located. 02/28/12

18. Multi-partite virus Infect both boot records and program files. Macro virus Infect data files. Example: Microsoft Office Word, Excel, PowerPoint and Access files 02/28/12

19. Melissa virus spread in Microsoft Word documents sent via e-mail. How it works ? Created the virus as word document Uploaded to an internet newsgroup Anyone who download the document and opened it would trigger the virus. Send friendly email messages to first 50 people in person’s address book 02/28/12

20. Melissa Virus was the fastest spreading virus ever seen. Forced a number of large companies to shut down their e-mail systems. 02/28/12

21. Contained a piece of code as an attachment. Double Click on the attachment triggered the code. Sent copies of itself to everyone in the victim’s address book Started corrupting files on the victim’s machine. 02/28/12

22. Code Red made huge headlines in 2001 It slowed down internet traffic when it began to replicate itself. Each copy of the virus scanned the internet for Windows NT or Windows 2000 that don’t have security patch installed. Each time it found an unsecured server, the virus copied itself to that server. 02/28/12

23. Designed to do three things Replicate itself for the first 20 days of each month Replace web pages on infected servers with a page that declares “Hacked by Chinese” Launch a concreted attack on the White House Web server. 02/28/12

24. The Morto virus emerged in the summer of 2011. It attempts to propagate itself to additional computers via the Remote Desktop Protocol (RDP). Morto spreads by forcing infected systems to scan for servers allowing RDP login. Once Morto finds an RDP-accessible system, it attempts to log in to a domain or local system account named 'Administrator' using a number of common passwords. 02/28/12

25. To avoid detection by users, viruses employ different deception methods They do not make themselves to change the date of last modified increase file sizes damage the files 02/28/12

26. They kill the tasks associated with antivirus software before it can detect them. 02/28/12

27. Take regular backups (including OS) on different media, unconnected to the system (most of the time) 02/28/12 How to prevent damages caused by viruses?

28. Use backups on optical media like CD and DVD (read-only), as they can no longer be affected by viruses. Use an OS on a bootable, to start the computer if the installed OS become unusable. 02/28/12 How to prevent damages caused by viruses?

29. Install reliable anti-virus software the most important step you can take towards keeping your computer clean of viruses Update your anti-virus software regularly variations of viruses and new ones can be slipped if your software is not current 02/28/12

30. Get immediate protection Configure your anti-virus software to boot automatically on start-up and run at all times 02/28/12

31. Don't automatically open attachments ensure that you examine and scan email and other attachments before they run as they might contain viruses Scan all incoming email attachments Do not open any email attached files if the subject line is questionable, unexpected or the source (address) is unknown, suspicious or untrustworthy 02/28/12

32. Delete chain emails and junk email Do not forward or reply to any of them, they clogs up the network Some viruses can replicate themselves and spread through email as a chain 02/28/12

33. Be careful when downloading files from the Internet Ensure that the source is a legitimate and reputable one save all downloads to one folder and test them with your own anti-virus software before use 02/28/12

34. Backup your files on a regular basis Always scan new files for viruses before you use them 02/28/12

35. If your computer is on a network, make sure you have security steps in place to prevent unauthorized users putting files on your computer 02/28/12

36. Take care using USB flash cards, CDs, zip and floppy disks The more computers flash cards, CDs, zip cards and floppies have been used on, the better the chance of a virus infecting them – clean them before use 02/28/12

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