Self Study of Narzullayev Shakhzod

Self Study of Narzullayev Shakhzod

• WHAT IS A "VIRUS"?

• Computer viruses are called viruses because they share some
• of the traits of biological viruses.
• A computer virus passes from computer to computer like a biological virus passes from person to person.

• BIOLOGICAL VIRUSES
• A biological virus is not a living thing
• A virus is a fragment of DNA inside a protective jacket
• A biological virus must inject its DNA into a cell

• COMPUTER VIRUSES
• A computer virus must piggyback on top of some other program or document in order to get executed
• Once it is running, it is then able to infect other programs or documents

• WHAT IS A "VIRUS"?

• VIRUS HISTORY

• Traditional computer viruses were first widely seen in the late 1980s
• Viruses took advantage of these three facts to create the first self-replicating programs!

• FIRST FACTOR
• Spread of personal computers

• SECOND FACTOR
• Use of computer "bulletin boards"

• THIRD FACTOR
• The floppy disk

• 1. FILE INFECTORS VIRUSES
• a. Embedded in program
• b. Runs when program gets executed
• c. Loads in memory
• d. Cycle continues through sharing files
• 2. BOOT-SECTOR VIRUSES
• a. Load viruses into memory
• b. Infect the boot sector on floppy disks and hard disks
• 3. MACRO VIRUSES
• a. Infects data files
• b. Executed in embedded scripts
• c. Inserts copies of itself into other documents
• d. Spreads by sharing data files

• CLASSES OF VIRUSES

• 1. Large size of today's programs (executable)
• 2. Operating systems now protect the boot sector

• EXECUTABLE AND BOOT SECTOR VIRUSES
• ARE NOT VERY THREATENING ANY MORE

• CLASSES OF VIRUSES

• E-MAIL VIRUSES

• E-MAIL VIRUSES ARE THE LATEST INVENTION

• Melissa Virus (March 1999)
• a. Embedded into Word document
• b. When opened, sent to first 50 email addresses in address book
• c. Included a friendly note making it look harmless
• d. If opened by any of the recipients, sent to another 50
• addresses of the current recipient
• The ILOVEYOU Virus (May 2000)
• a. Attachment is a piece of code
• b. When executed, sent itself to everyone in the address book
• c. Corrupted files

• ORIGINS

• THREE REASONS PEOPLE CREATE VIRUSES

• The same psychology that drives vandals and arsonists
• The thrill of watching things destroyed
• Bragging rights, or the thrill of doing it

• FIGHTING VIRUSES

• ANTIVIRUS PROGRAMS
• - Norton Antivirus (Symantec)
• - VirusScan (McAfee)
• - F-Secure Anti-Virus (F-Secure)

• No anti-viruses guarantee 100 percent protection from viruses!!!

• STATISTICS

• NUMBER OF INFECTED FILES BY COUNTRY, WITHIN THE LAST 30 DAYS

• 0-100
• 101-1000
• 1001-10,000
• 10,001-100,000
• 100,001+