Preventive Measures To Avoid Spreading Viruses Computer Science Essay

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booting off of a Live CD or putting the hard drive into another computer and booting from the other computers operating system though care must be taken not to transfer the virus to the new computer.

The only best way to avoid viruses is keeping the system as stand alone with out communicating with any other system. Even floppies, pen drives and blue tooth are should not used for computer. But in to-days world it is not at all possible because communication plays a vital role in modern world.

B. Anti - virus software.

Many users install anti-virus software that can detect and eliminate known viruses after the computer downloads or runs the executable. There are two common methods that an anti-virus software application uses to detect viruses. The first, and by far the most common method of virus detection is using a list of virus signature definitions. This works by examining the content of the computer's memory (its RAM, and boot sectors) and the files stored on fixed or removable drives (hard drives, floppy drives), and comparing those files against a database of known virus "signatures". The disadvantage of this detection method is that users are only protected from viruses that pre-date their last virus definition update. The second method is to use a heuristic algorithm to find viruses based on common behaviors. This method has the ability to detect viruses that anti-virus security firms have yet to create a signature for.

Some anti-virus programs are able to scan opened files in addition to sent and received e-mails 'on the fly' in a similar manner. This practice is known as "on-access scanning." Anti-virus software does not change the underlying capability of host software to transmit viruses. Users must update their software regularly to patch security holes. Anti-virus software also needs to be regularly updated in order to prevent the latest threats.

One may also minimise the damage done by viruses by making regular backups of data (and the operating systems) on different media, that are either kept unconnected to the system (most of the time), read-only or not accessible for other reasons, such as using different file systems. This way, if data is lost through a virus, one can start again using the backup (which should preferably be recent).

If a backup session on optical media like CD and DVD is closed, it becomes read-only and can no longer be affected by a virus (so long as a virus or infected file was not copied onto the CD/DVD). Likewise, an operating system on a bootable CD can be used to start the computer if the installed operating systems become unusable. Backups on removable media must be carefully inspected before restoration. The Gammima virus, for example, propagates via removable flash drives

C. Take no action while connecting USB drive

We can protect your PC by just following the simple steps below while connecting USB drive.

Connect Pen Drive or USB drive to Computer.

Then a dialogue window will popup asking to choose among the options as shown in the figure.

Fig.1 Take no action while connecting USB drive

Don't choose any of them, just simply click Cancel.

Now go to Start--> Run and type cmd to open the Command Prompt window.

Now go to My Computer and Check the Drive letter of your USB drive or Pen Drive. ( E.g. If it is written Kingston (I:) , then I: will be the drive letter .)

In the Command Window ( cmd ) , type the drive letter: and Hit Enter (I:) .

Now type dir/w/o/a/p and Hit Enter.

You will get a list of files . In the list , search if anyone of the following do exist .


New Folder.exe






RVHost.exe or any other files with .exe Extension .

If there is any one of the files above , Run the command attrib -h -r -s -a *.* and Hit Enter.

Now Delete each File using the following Command del filename ( E.g del autorun.inf ) .

Now scan USB drive with the anti virus we have to ensure that we made our Pen Drive free of Virus.

Now we removed the viruses manually and confirmed with Antivirus software.

D. Disable Write Access to USB Hard Disk and Flash Key Drives

There is a registry hack that able to disable the USB drive access to USB mass storage device such as flash drive, USB key, thumb drive, pen drive and portable hard disk while keeping the USB hardware device such as webcam, mouse, keyboard, printer and scanner connected to USB ports working as usual. However, the hack disables the USB access to disk drive completely. User cannot copy data to the USB disk storage, nor able to read any files and documents from the USB drive.

For user who just want to disable write access to the external removable USB mass storage disk drive, there is another registry hack of WriteProtect in StorageDevicePolicies registry key that able to restrict Windows system from writing to the USB disk drive, and hence effectively user to copy any sensitive or private data from the PC to USB key stick. The trick works in a similar way to write-protect feature used in floppy disk and backup tape which make the disk read-only, only that in this case, it’s system wide implementation that block any writing and recording of data to USB mass storage device.

To disable writing access to USB drives and make all USB drives has only read-only access, follow these steps:

Run Registry Editor (regedit).

Fig.2. run regedit.exe.

Navigate to the following registry key:


To revert and remove the blocked write access to USB drivers, just delete the StorageDevicePolicies registry key, or delete the WriteProtect registry entry, or change the value data for WriteProtect to zero (that is 0).

For user who doesn’t want to manually editing the registry, simply the following code to enable or disable the write protection (block writing attempt) to USB removable drive.

A. Disable the write protection

Type the following code and save to DisableWriteToUSB.reg file

Fig. 10 DisableWriteToUSB.reg file

Double click the DisableWriteToUSB.reg file

Fig. 11 DisableWriteToUSB.reg file icon

B. Disable the write protection

Type the following code and save to EnableWriteToUSB.reg file

Fig. 12 EnableWriteToUSB.reg file

Double click the EnableWriteToUSB.reg file

Fig. 13 EnableWriteToUSB.reg file icon

This method works in Windows XP SP2 and SP3, Windows Vista, Windows Server 2003 and 2008.

IV. Conclusion

Lot of viruses occupy space in disk and degrades the performance. Using these preventive measures space and time problems are solved to some extent. Public service systems also get protection from viruses. Thousands of DTP centers will get benefit by preventing from spreading viruses.