In early days, the information is kept in racks in the form of files and racks protected by locking. After inventing Data processing system (Computer systems) all the information is stored in the memory in the form of files. So, information security requirement increased. Automated tools are used to protect the data in the computer system. This type of security is the computer security.
After introducing distributed systems and Networks, the information is transmitted to others through communication facilities. Then Network security came into existence.
It can damage the operating system’s ability to control basic functions, and when applications programs are run, it can override activities also.
Two gentlemen in Pakistan, Basset Faro and Amada Alive created first ever virus BRAIN . Their program installed a copy of itself on every 360KB disk that was accessed and replaces the boot program which initiates the operating system.
Suriv-02 is the .exe Virus. IBM faced and outbreak of Cascade Virus and warned its users about Viruses.
In 1950’s and 1960’s scientists at Bell Laboratories created Viruses that battled each other trying to destroy opposing viruses without being caught.
concurrently with the operating system or application programs they have infected, carrying out their tasks either openly or hidden in the background. These virus programs can be classified as following:
Virus: It is also a type of computer program. It will get itself attached to any on the program. These programs for which the virus was attached is called host program. It cannot exist without the presence of any other program.
Worm: These programs don't require host programs. These work individually unlike as virus programs. These can also generate more copies themselves.
Torjon Horse: It is a stand-alone program like as worm, and it can work independently. These Viruses cannot prepare more copies themselves.
Dropper :When a virus program is encrypted to any program then that will be called a Dropper. No virus scanner will identify these types of virus programs. When these Droppers are executed it will be copied to the other programs. These Droppers are very useful for the virus growth.
Joke Program : These programs give us the illusion that there was some virus program. In reality it doesn’t pose any problem. These programs also cannot prepare their own copies.
Viruses are classified according to their working and the harm done by them. The classification is as follows:
Boot viruses :These types of Virus destroy the Boot records of Hard disk and Floppy disk. When we try to boot the system these Virus will be loaded onto the memory. Example : Michylangelo, Farm, Disk killer, and Stone Virus.
Program virus :These are also file Viruses. This will harm the files containing .bin, .com, .exe, .ovl, .drv, and .sys as their extension. When these programs are executed these will load into the memory and will be copied to other files also.
Example : Sunday cascade.
Multi Pirate viruses :This type of Virus creates harm to the program files. When they are executed they will be stored onto the memory and extends its limits to the boot records. After this whenever we boot the system the Virus will be copied to memory and transferred to the remaining files also.
Steallth virus :These types of viruses are generally classified as the clever virus. These viruses will not be caught for any type of virus scanners. When we try to read this program the control or the execution
According to a recent study conducted by the NCSA(N ational C omputer S ecurity A gency ), macro viruses were responsible for the largest number of infections (49 percent ). The most common source of macro virus infection was found to be e-mail attachments.
Symptoms of a Virus:
If a system was infected with a virus it will have some changes in the computer. The symptoms of a Virus are:
Decreasing the speed of the system.
Size of the file increases rapidly.
Some files will be automatically deleted by ignoring the user.
Use physical safeguards to protect your system from outsiders.
Restrict access to your system physically and technically.
Scan e-mail attachments before reading them.
The ultimate protection is your backups.
Using a Antiviral software:
Though we have taken many precautions the system will be affected by Virus. Even if the virus on your system is very malicious, chances are that it will be activated only on a specific date or a similar trigger. At that we will require a Virus scanner to scan and to destroy the Virus. Due to the ever-evolving forms of attack, we can never be sure about our security.
At present there are many types of Antiviral software available in the market. They are F-Secure antivirus 3.0, Norton antivirus 4.0, PC-Cillin 97-3.0, Quick heal express etc. Full featured protection that includes scanning and activity trapping components. In addition such a package includes access control capability,which limits the ability of virus to penetrate a system. In this way we can try to protect the system. But viruses will be increasingly to spread propaganda and misinformation. So, extensive protection will be required.