Viruses

1. Viruses Survey of Computer Information Systems By: Jenny Ramirez http://wiki.gc.maricopa.edu/display/ls/CIS105+Poster+Session+No.+3

2. Cyberattacks • Cyberattacks can take the form of software that is distributed and executed on a computer without the user’s knowledge for the purpose of corrupting or disrupting systems. • The most common of these types of programs are viruses, which due to their malicious nature are sometimes referred to as malware.

3. Definitions • Viruses- A virus is a small piece of software that piggybacks on real programs. A virus might attach itself to a program such as a spreadsheet program. Each time the spreadsheet program runs, the virus runs, too, and it has the chance to reproduce, by attaching to other programs. • Antivirus software- A antivirus software uses several techniques to find viruses from infecting the system. • Trojan horse- A Trojan horse is a program you download, when you run the program it erases your disk.

4. History of Viruses Traditional computer viruses were first widely seen in the late 1980’s, and they came about because of several factors. the spread of personal computers (PCs) the use of computer bulletin boards the floppy disk

5. History of Viruses Continued • Home computers were nearly non-existent or they were toys. Real computers were rare, and they were locked away for use by "experts." Real computers started to spread to businesses and homes because of the popularity of the IBM PC. By the late 1980’s, PCs were widespread in businesses, homes and college campuses. • People could dial up a bulletin board with a modem and download programs of all types. Games were extremely popular, and so were simple word processors, spreadsheets and other productivity software. Bulletin boards led to the precursor of the virus known as the Trojan horse. • It all started 20 years ago with a virus called "Brain" that was spread by floppy disks.

6. Brain • System sectors are special areas on your disk containing programs that are executed when you boot (start) your PC. System sectors are invisible to normal programs but are vital for correct operation of your PC. 1986 - Brain was written by Basit as well as Amjad, these two brothers had a computer store in Pakistan.The reason that they wrote the virus was that they got tired of people making illegal copies of the programs that was sold in the computer store. Brain, a boot sector virus that exhibited stealth techniques to avoid detection. Brain also changed the volume label of the disk drive.

7. Types of Viruses Computer viruses were labeled as viruses because of the fact that they are similar to that of biological viruses in the aspect of multiplying themselves. Similarly they find a host and then infect and multiply themselves. Numerous viruses have been designed to infect systems in different ways and avoid detection. • Boot virus • Direct action virus • Directory virus • Encrypted virus • File virus • Logic Bomb • Macro virus • Multipartite virus • Overwrite virus • Polymorphic virus • Resident virus • Time bomb

8. Boot Virus Direct Action Virus Infects a computer’s startup program so that the virus becomes active as soon as the computer starts up. Drops payload and spreads when defined conditions are met; can usually be removed without damage to infected files using antivirus software. Directory Virus Encrypted Virus Changes the paths that indicate the location of files on the computer system. Encrypts itself so as to be hidden from scans; before performing its task it decrypts itself

9. File Virus Logic Bomb Attaches to other software so that the virus instructions are processed along with the software instructions. Delivers its payload when certain system conditions have been met. Macro Virus Multipartite Virus Infects macros embedded in data files created with other software; infects and spreads to other files viewed by that software. Creates multiple types of infections using several techniques, making the virus difficult to detect and remove.

10. Overwrite Virus Polymorphic Virus Deletes information contained in the files that it infects, rendering them partially or totally useless. Encrypts itself in a different way every time it infects a system, making it very difficult to detect. Resident Virus Time Bomb Hides permanently in the system’s memory, controlling and intercepting all system operations. Hides permanently in the system’s memory, controlling and intercepting all system operations.

11. How can I protect my computer from viruses? The number one tool against viruses is antivirus software. • You should install the latest versions of anti-virus software on your desktop computer to protect it from viruses and keep it up to date. • Configure the anti-virus software for increased protection. • Back up your data on a regular basis • Don't open or preview mail from unknown sources. • Be very cautious of any email attachments you receive. If you do not know who it is from, delete the message.

12. Don’t Freak Out! Remember, most viruses can be removed without permanent damage to your system, and most virus infections can be prevented. With proper care, your computer can remain virus-free.

13. Summary Viruses came about since back in the 1980’s. There are many different types of viruses, which spread and affect in different ways. The number one tool to prevent viruses is by installing antivirus software. Viruses can be removed without damaging the whole system. You just have to take care of your computer and keep everything updated.

14. Works Cited • http://support.microsoft.com/kb/129972 • http://www.microsoft.com/protect/computer/basics/virus.mspx • http://antivirus.about.com/ • http://vlaurie.com/computers2/Articles/defend.htm • Succeeding with Technology, second edition, (Pg 561-565)