Virus Dangers
People have to be always
cautious about computer viruses, because
viruses can spoil people’s money, time resources and irreplaceable data.
Virus Classifications
A computer virus is explained as
a computer program designed to replicate itself by infecting other files or
system areas and then making copies of itself. It may be benign or will operate
without the knowledge or desire of the computer viruses can be categorized in to one of following broad virus
categories.
Viruses- Usually the virus
activity within a single computer
Trojan horse -when run, a Trojan horse does something harmful to
the computer system, but disguised as
something useful. Unlike viruses , Trojan horses usually do not make copies of
themselves.
Worm- Is a computer program that propagates
it self across computers, creating copies of itself in each computer, infecting
the entire network.
The following summarized how the
viruses get evolved over time , expanding their capabilities and scope.
Macro viruses; These viruses come
attached to documents and when that document is opened the virus gets activated.
Parasitic or File Infector
viruses: These viruses attach themselves to or replace executable files, such
as, files with extensions.com, .exe or even.sys, .drv and bin.
Bootstrap viruses : Boot sector
is a small portion of a disk reserved for the bootstrap loader program of an
operating system. When a bootstrap virus infects this bootstrap program,
the virus gets activated at each time
the operating system is loaded.
Multi-partite viruses: These
viruses often infect multiple targets, for instance both files and bootstrap of
a disk.
Polymorphic viruses: These viruses are capable of
mutating over time to escape from anti-virus software.
Stealth viruses: These viruses
can conceal themselves in memory.
Retro viruses: These viruses are
designed to attack and defeat anti-virus software.
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