COMPUTER VIRUSES
Computer viruses are small software programs that are designed to spread from one computer to another and to interfere with normal computer operation .in other words, the computer virus spreads by itself into other executable code or documents .the term ‘computer virus’ was first formally defined by fred cohen in 1983 computer viruses never occur naturally they are always induced by people
The most viruses work silently making sure that the user is unaware of the infection. It spreads from program to program and disk to disk, manipulating valuable information or data.
Majority of the viruses are created for sheer fun .such as, on a certain day of the month, hearing a clicking sound every time press a key. But some viruses are written for hateful motives like financial or professional gains or spreading panic and terror.
INDICATION OF VIRUS INFECTION
Viruses may cause a lot of damage to computer and network by different ways .some indications of virus infection are:
1. The file formats are automatically changed.
2. New files keep appearing on the system but we do not know where they come from.
3. The file on the computer automatically deleted.
4. The computer unexpectedly starts rebooting.
5. The operating system will not start at all even though you have not made any system changes or you have not installed or removed any programs.
6. Program takes more time than usual time to load in the memory.
7. The computer frequently stops responding.
8. Files have strange names that we do not recognize.
9. Inability to access the hard drive or disk drives.
10. Installed memory becomes less without any reason.
11. Hard disks show no space though there is enough space.
12. Programs or files become missing.
13. Your computer slows down without any reason.
TYPES OF VURUSES
There are many kinds of viruses .the level of destruction by each virus varies widely viruses are classified as:
BOOT SECTOR VIRUS
Boot sector virus infects the floppy disks or hard disks. This type of virus can, at least theoretically, also exist on other media such as CD, DVD ROM, flash drives and other removable storage. It replaces the boot record program which is responsive for loading the operating system in memory, copying it elsewhere on the disk or overwriting it.when the system the system is booted with such a hard disk, it enters the memory and whenever the computer reads or written any disk ,it will infect the files in the disk.
PROGRAMMING VIRUS
A program virus infects executable program files. a file infecting virus overwrites code or inserts infected code into a executable file , when the infected file is executed ,the virus becomes active in the memory ,making copies of it and infection files on disk.
MACRO VIRUS
A micro virus infects data files which are accessed more frequently by t he computer users .these infect data files, such as word documents or excels spreadsheet, rather than programs. The infected data files can be spared the virus very quickly. Such as overwrite each file they infect and completely destroy the data in the file. If a macro virus has infected these files, it has the potential to damage the document or other computer software. When an infected file is opened, the macro virus releases a sequence of actions that begin automatically .these actions cause damage to the computer and its applications. These macros are usually stored as part of the document or spreadsheet and can travel to other system when these files are transferred to another computers.
MULTIPARTITE VIRUS
A multipartite virus is a computer virus that infects and spreads in multiple ways, it attacks both the boot sector and the program files at the time for a complete cleanup, all parts of the virus must be removed. it is also called hybrid virus.
POLYMORPHIC VIRUS
Polymorphic viruses are complex file infectors that can create modified versions of itself to avoid detection yet retain the same basic routines after every infection. A polymorphic virus changes its virus signature every time it replicates and infects a new file in an order to keep from being detected by an antivirus program. Despite its capabilities the polymorphic virus is not invulnerable by taking the right steps you can protect yourself from this constantly evolving threat.
TROJAN
Trojan is a program that hides its true intention. It is a destructive program disguised as a game application or utility .it causes problems like killing background system processes deletion hard drive data and corrupting file allocation systems. When it is activated ,it caused damage although appearing to be useful.trojan are encountered as email attachments with tempting names that prompt people to open them.
MALWARE
Malware and malicious software`s are programs or applications which get installed on your computer system without your permissions and are designed to penetrate or damage our computer system or using privilege escalation to gain remote administrator access . In 1949 jon von Neumann`s “theory of organization of complicated automata” introduced the idea of malware virus .it discussed how organisms self reproduce.
SPYWARE
Spyware is used for many purpose .usually it aims to track and sell your internet usage data, capture your credit card or bank account information, or steal your personal identity. Spyware is threat to businesses and individual users since it can steal sensitive information and harm your network. Spyware is unwanted software that infiltrates your computing device, stealing your internet usage data and sensitive information. Program enter a computer system as part of useful software .spyware monitor the activities going on in your computer and can send this information through the network this information can be misused to gain control of your computer system remotely or to access information stored in your computer.
ADWARE
Adware programs usually display unwanted pop us advertising a particular product or install unnecessary applications on your computer system that can reduce you computers productivity and efficiency. Adware is more annoying than dangerous .there will be constant banners, in text ads that appear inside your browser window while surfing the internet. Sometimes adware can even alter your browser settings and cause your browser to open WebPages that you do not authorize .adware tends to be difficult to get rid of and can required specialized virus software to remove.
WORMS
Worms are more complicated viruses that automatically send themselves to other computers over a network without any human interaction or assistance worms take control of certain software programs on a computer to spread to other computers worms can affect data files as well as application files. Once a worm enters your system it sort of scouts the environments looking for opportunities such as emailing itself to everybody in your contact list. So the key differentiating characteristic of a worm virus is that is can replicate itself, almost as though it were a biological virus.
RETRO VIRUS
Retro virus is another type virus which tries to attack and disable the antivirus application running on the computer also called anti-antivirus.
MASS MAILER VIRUS
Mass mailer viruses search email program like MS outlook for email addresses which are stored in the address book and replicate by emailing themselves to the addresses stored in the address book of the email program. Besides overwhelming servers and networks with massive volumes of emails mass mailing worms often cause serious performance issues for infected systems.
STEP TO INSURE SAFETY
1. Scan your computer regularly
2. Do not open email attachments without scanning them.
3. Install a firewall to filter the incoming and outgoing messages
4. Adjust security settings in your browser to ensure maximum protection
5. Backup your files in a separate location
6. Install an antivirus program and make sure that you keep it updated
7. Use software from trusted sources can new software programs for viruses before installing them
8. Never use pirated software
9. Keep a bootable disk ready with you to access or boot the system in case of system crash due to virus infection.
10. Scan files downloaded from the internet or those transferred through a network or removable disk.
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1 Comments
Very nice writings with simple and meaningful
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