2. 1. File virus
• The file virus affects executable programs
(.exe)
• It replaces a part of original code file with
a malicious code, thus destroying the file
3. 2. Boot sector virus
• The 1st sector of the outermost track in floppy disk
contained a small program known as bootstrap
loader program.
• when computer was switched on, this program
used to load OS from floppy disk to the main
memory of the computer.
• A boot sector virus substitutes itself for bootstrap
loader. Virus gets automatic loaded into main
memory.
• Once loaded it starts affecting all files on disk.
6. 1. Trojan Horse: damages files by merging
unwarranted program code with
authorized programs.
2. Worms: this program duplicates its own
code.
3. Salami techniques: robs small amount of
money from user account and user
remains unaware.
4. Eaves Dropping: allows a person to
observe some message transmitted to
other people.
7. 5. Wire tapping: it has special transmission path
to divert flow of data from original user to
unauthorized user.
6. Stealth virus: these virus avoids self detection
by antivirus.
7. Logic bombs: these cause computer to
malfunction.
8. Data diddling: performs unauthorized
modifications of data and user is not aware of
it.
8. Antivirus software are computer programs that
attempt to identify, neutralize or eliminate malicious
software.
