Essay/Term paper: Computer virus

Essay, term paper, research paper:  Technology

COMPUTER VIRUSES Cateye <1>WHAT IS A COMPUTER VIRUS: The term usually used to define a computer virus is: ' A computer virus is often malicious software which replicates itself' [ Podell 1987 for similar definition ] - COMPUTER VIRUSES ARE BASICALLY PROGRAMS, LIKE A SPREADSHEET OR A WORD PROCESSOR. - PROGRAMS WHICH CAN INSERT EXECUTABLE COPIES OF ITSELF INTO OTHER PROGRAMS. - PROGRAMS THAT MANIPULATES PROGRAMS, MODIFIES OTHER PROGRAMS AND REPRODUCE ITSELF IN THE PROCESS. Comparing Biological viruses & Computer viruses ************************************************************* * Attack specific * Attack specific * * body cells * programs (*.COM *.EXE) * ************************************************************* * Modify the genetic information * Manipulate the program: * * of a cell other than previous 1* It performs tasks * ************************************************************* * New viruses grow in the * The infected program produces * * infected cell itself * virus programs * ************************************************************* * Infected cells aren't infected * Program are infected only once* * more than once by the same cell* by most programs* ************************************************************* * An infected organism may not * The infected program can work * * exhibit symptoms for a while * without error for a long time * ************************************************************* * Not all cells with which the * Program can be made immune * * virus contact are infected * against certain viruses * ************************************************************* * Viruses can mutate and thus * Virus program can modify * * cannot be clearly told apart * themselves & possibly escape * * * detection this way * ************************************************************* However, " computer virus " is just another name for a class of programs. They can do anything that another program can. The only distinguishing characteristic is the program has ability to reproduce and infect other programs. <2>WHAT KIND OF PROGRAM ARE CHARACTERIZED AS A VIRUS PROGRAM: - PROGRAM WHICH HAS CAPABILITY TO EXECUTE THE MODIFICATION ON A NUMBER OF PROGRAMS. - CAPABILITY TO RECOGNIZE A MODIFICATION PERFORMED ON A PROGRAM.(THE ABILITY TO PREVENT FURTHER MODIFICATION OF THE SAME PROGRAM UPON SUCH RECONDITION.) - MODIFIED SOFTWARE ASSUME ATTRIBUTES 1 TO 4. <3>HOW DOES A VIRUS SPREAD: A computer virus can only be put into your system either by yourself or someone else. One way in which a virus can be put into your computer is via a Trojan Horse. -TROJAN HORSE IS USUALLY CONTAMINATED IN DISKS WHICH ARE PARTICULARY PIRATED COPIES OF SOFTWARE. IT IS SIMPLY A DAMAGING PROGRAM DISGUISED AS AN INNOCENT ONE. MANY VIRUSES MAYBE HIDDEN IN IT, BUT T.H. THEMSELVES DO NOT HAVE THE ABILITY TO REPLICATE. Viruses also can be spread through a Wide Area network (WAN) or a Local Area Network (LAN) by telephone line. For example down loading a file from a local BBS. BBS(bulletin board system)-AN Electronic mailbox that user can access to send or receive massages. However, there seems to be countless numbers of ways to become infected. Every-time you down loads a program from somewhere or borrowed a disk from a friend, you are taking a risk of getting infected. <4>DAMAGES AND SIGNS OF INFECTION: a.> Fill Up your P.C. with Garbage: As a virus reproduces, it takes up space. This space cannot be used by the operator. As more copies of the virus are made, the memory space is lessened. b.> Mess Up Files: Computer files have a fixed method of being stored. With this being the case, it is very easy for a computer virus to affect the system so some parts of the accessed files cannot be located. c.> Mess Up FAT: FAT(the File Allocation Table) is the method used to contain the information required about the location of files stored on a disk. Any allocation to this information can cause endless trouble. d.> Mess Up The Boot Sector: The boot sector is the special information found on a disk. Changing the boot sector could result in the inability of the computer to run. e.> Format a Disk/ Diskette: A virus can simply format a disk as the operator would with the format or initialise command. f.> Reset The Computer: To reset the computer, the operator or the user only has to press a few keys. The virus can do this by sending the codes to the operating system. g.> Slowing Things Down: As the name implies, the object of the virus is to slow down the running line of the program. h.> Redefine Keys: The computer has been program to recognize that certain codes/ signals symbolize a certain keystroke. The virus could change the definition of these keystrokes. i.> Lock The Keyboard: redefining all keys into an empty key. <5>WHAT TO DO AFTER VIRUS ATTACKS: When signs of a virus attack have been recognized, the virus has already reproduced itself several times. Thus, to get rid of the virus, the user has to hack down and destroy each one of these copies. The easier way is to: 1. Have the original write protected back-up copy of your operating system on a diskette. 2. Power down the machine. 3. Boot up the system from the original system diskette. 4. Format the hard disk. 5. Restore all back-ups and all executable program. *If it's not effective, power down and seek for professional help* <6> TYPE OF VIRUSES: a.> OVER-WRITING VIRUSES b.> NON-OVERWRITNG VIRUSES c.> MEMORY RESENDENT VIRUSES <7>PRACTICE SAFE HEX: Viruses are a day to day reality. Different activities leads to different exposure. To protect oneself from a virus, several things can be done: 1. Avoid them in the first place. 2. Discovering and getting rid of them. 3. Repairing the damage. The simple thing that can cut down on exposure rate are to: avoid pirate software, checking programs that have been down loaded form the BBS before running them. Make sure that you have sufficient backups. <8> ANTIVIRUS PRODUCTS COMPANY: The pace at which new antiviral products have been pouring onto the market has accelerated rapidly since the major infection of 1988. Indeed, by early 1989, there were over 60 proprietary products making varied claims for effectiveness in preventing or detecting virus attacks. For: IBM PCs & Compatibles DISK DEFENDER PC SAFE McAFEE SCAN DIRECTOR TECHNOLOGIES THE VOICE CONNECTION McAFEE ASSOCIATES 906 University Place 17835 Skypark Circle 4423 Cheeney Street Evanston, IL 60201 Irvine, CA 92714 Santa Clara, CA 95054 TEL: (408) 727-4559 TEL: (714) 261-2366 TEL: (408) 988-3832 Price: $ 240.00 U.S. Price: $ 45.00 U.S. Price: $ 80.00 U.S. Class : HARD.2 Class : SOFT.1 Class: SOFT.3 For: Macintosh Plus, SE, & II(Apple) VIREX HJC SOFTWARE P.O. BOX 51816 Durham, NC 27717 TEL: (919) 490-1277 Price: $ 99.95 U.S. Class : SOFT.3 *Class 1(infection prevention class)* Most Class 1 products are unable to distinguish between an acceptable or unacceptable access to an executable program. For example, a simply DOS COPY command might cause the waring appear on screen. *Class 2(infection detection class)* All Class 2 products are able to distinguish all DOS commands. Addition to Class 1's prevention fuction, it is able to protect all COM and EXE files from infection. *Class 3(Top class)* Class 3 products are cable of both prevention & detection fuctions. And they are cable of removing the infection viruses. <1>. COMPUTER VIRUSES a high-tech disease WRITTEN BY: RALF BURGER PUBLISH BY: ABACUS, U.S.A <2>. DATA THEFT WRITTEN BY: HUGO CORNWALL PUBLISH BY: PONTING-GREEN, LONDON <3>. COMPUTER VIRUSES,WORMS,DATA DIDDLERS,KILLER -PROGRAMS, AND OTHER THREATS TO YOUR SYSTEM WRITTEN BY: JOHN McAFEE & COLIN HAYNES PUBLISH BY: ST.MARTIN'S PRESS, U.S.A ************************************************* * COMPUTER VIRUSES CRISIS * THE SECRET WORLD * * WRITTEN BY: PHILP E FITES * OF COMPUTER * ****************************** WRITTEN BY: * * COMPUTE'S COMPUTER VIRUSES * ALLAN LNNDELL * * WRITTEN BY: RALPH ROBERTS * * *************************************************