FAQs on Viruses

1.

 Should I reformat the hard disk if there is a virus problem?
2. How do viruses spread?
3. How can a virus be avoided?
4. How do I know I have a virus?
5. Do hoax viruses exist?
6. Can viruses spread from one type of computer to another?
7. Does setting a file's attributes to READ ONLY protect it from viruses?
8. Why does my scanner report an infection only sometimes?
9. Can a virus be avoided by avoiding shareware, free software, games, etc.?
10. Can a PC not running DOS be infected with a common DOS virus?
11. If my hard disk's file system is unintelligible, does it mean that I have a virus?
12. Is software alone sufficient to protect a computer system?
13. Is hardware protection useful?
14. Does Write-protection stop the spread of viruses?
15. Do password/access control systems help protect files from viruses?
16. Do local area networks (LANs) facilitate the spread of viruses?
17. Can a virus infect a mainframe computer?
18. Is disinfecting a safe procedure?
19. Is it possible to get infected through e-mail, BBS message forums or USENET News?
20. What are virus simulators?
21. Could an anti-virus program itself be infected?
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1.

 Should I reformat the hard disk if there is a virus problem?
Reformatting your hard disk is not necessary and most probably will not eradicate the virus.
2. How do viruses spread?
  • A PC can be infected with a boot sector virus or partition sector virus from an infected floppy disk in drive A. They normally do not spread across a network but via floppy disks. They may come from sources like unsolicited demonstration disks, brand-new software, disks used on your PC by others.
  • A file virus infects other files when the program to which it is attached is run. This can spread across a network very quickly. The sources are like unsolicited demonstration disks, brand-new software, disks used on your PC by others and also Internet FTP sites and bulletin boards.
  • A multipartite virus infects boot sectors and files.
3. How can a virus be avoided?
There is no guaranteed way to avoid a virus infection. It is best to take precautions and minimize risk:

  • make sure you have a clean boot disk, test with the latest anti-virus software.
  • use reputable, up-to-date and properly-installed anti-virus software regularly.
  • always run a memory-resident scanner to monitor disk access and executable files before they're run.
  • check all new systems and all floppy disks when they're brought in with a good virus-scanning program.
  • scan pre-formatted diskettes before use.
  • make sure your data is backed up regularly
4. How do I know I have a virus?
Some common indications of the presence of a virus are

  • unusual screen displays or messages
  • slowing down of the operation of the computer
  • longer disk activity, or strange hardware behavior
  • it may cause a drive to be accessed unexpectedly
  • a change in the length of executable files, a change in their content, or a change in their file date/time in the Directory listing
  • unaccounted use of memory or a reduction in the amount normally shown for the system

It is best to scan regularly even if everything seems to be working right.
5. Do hoax viruses exist?
Yes. The following "viruses" are hoaxes:

  • Good Times
  • Deeyenda Maddick
  • Irina
  • Join the Crew
  • Returned or Unable to Deliver
  • Naughty Robot

Normally Virus Warnings that you appear unexpectedly in your e-mailbox asking you to pass the message along are likely to be a hoax.

6. Can viruses spread from one type of computer to another?
At present there is no known virus, which is capable of doing so. Such viruses though possible, are highly unlikely.
7. Does setting a file's attributes to READ ONLY protect it from viruses?
Generally  it does not happen. The Read Only attribute may protect your files from a few viruses but most simply override it, and infect normally. Read Only not a sure protection against viruses but can be used.
 
8. Why does my scanner report an infection only sometimes?
A part of a virus could exist in RAM without being active at times. If the scanner reports a virus only sometimes, it could be due to the operating system buffering diskette reads or harmlessly keeping disk contents that include a virus in memory. There is also a possibility of scan strings being left in the memory.
9. Can a virus be avoided by avoiding shareware, free software, games, etc.?
Not necessarily. Even commercial software could contain viruses.

One should focus more on being cautious rather than totally avoiding and should scan regularly.
10. Can a PC not running DOS be infected with a common DOS virus?
There are possibilities of this happening.

It could happen in an operating system, which boots from a DOS disk and loads a standard DOS executable that takes complete control of the system from DOS.

Also possible is in the case of a system running NetWare or a self-loading OS, such as Unix, NeXTStep486, Windows NT or OS/2. The final possibility is any OS that offers a DOS box or DOS emulator to run DOS programs can, potentially, run a virus-infected DOS program.
11. If my hard disk's file system is unintelligible, does it mean that I have a virus?
Corruption of file systems can be caused by many other things besides viruses. It is best to seek expert help before proceeding to fix it.
12. Is software alone sufficient to protect a computer system?
Although software defenses significantly reduce the risk of virus infection, it is not a perfect solution.
13. Is hardware protection useful?
There are many benefits of hardware protection, like
  • write protection for hard disk drives
  • memory protection
  • monitoring
  • trapping unauthorized system calls

There are many more benefits but the stronger hardware-based protection is, the more likely it is to interfere with the normal computer operation.
14. Does Write-protection stop the spread of viruses?
Although it may stop viruses from spreading to the disk that is protected, it does not prevent a virus from running.
15. Do password/access control systems help protect files from viruses?
Password /access control systems are basically designed to protect the user's data from other users and are not effective in protecting files from viruses.
16. Do local area networks (LANs) facilitate the spread of viruses?
LANs can actually facilitate as well as stop the spread of viruses. The presence of a LAN gives users access to common pool of executable programs, thus reducing the need diskette swapping and software exchange.

But if the LAN has lax security and is not well managed, it could help a virus to spread like wildfire.
17. Can a virus infect a mainframe computer?
It is possible. In fact they spread very quickly and effectively on mainframe systems. But no actual infected cases have been seen so far.
18. Is disinfecting a safe procedure?
It is a totally safe procedure provided the disinfecting process completely restores the non-infected state of the object. The virus must not only be removed from the object, but all system attributes must be restored.
19. Is it possible to get infected through e-mail, BBS message forums or USENET News?
Normally this does not happen. Since viruses are programs, which must be executed to do anything and e-mails, etc are only text data, only reading them will not cause infection.

But if your computer uses ANSI screen and keyboard controls, you may be susceptible to an ANSI bomb.
20. What are virus simulators?
Virus simulators do not generate viruses. They are of three types:

  • one demonstrates the audio- and video-effects of some real computer viruses
  • one simulates a virtual environment in which users can manipulate the simulated objects, letting the simulated viruses infect the simulated files on the simulated disks, watching every step of the process, without a danger of real infection
  • one generates files containing scan strings used by some scanners to detect real viruses.

They are used for educational purposes, installation checks and as a test of the quality of the anti-virus defense.
21. Could an anti-virus program itself be infected?
Yes it is possible. In such a case it is advisable to obtain this software from good sources, and to trust results only after running scanners from a clean system. But there are situations where a scanner appears to be infected when it isn't.
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