Section 8.5
8 Legal Issues And Data Security
8.5 Viruses And Trojans
8.5.1 Viruses
A computer virus is a portion of software that is able to copy itself and usually
has an undesirable effect of computer data.
Sources Of Infection
- Internet downloads
- Floppy disks
- Email attachments
- Local area networks
Virus Categories
Most viruses activate and replicate under certain conditions.
- Time Bombs - triggered by a particular date.
- Logic Bombs - triggered by a set of conditions.
8.5.2 Virus Protection And Precautions
Anti-virus software should be installed on all systems where there is a risk
of infection.
The following precautions can be taken to slow down the spread of viruses.
- Internet downloads should only be made from trustworthy sites.
- No removable disks should be used in a computer unless first being
virus checked.
- Macros should be disabled where possible.
- Floppy disks can be inoculated against boot sector viruses.
- New software on floppy disks should remain write-protected.
- Hardware engineers who move from network to network should ensure that
their disks are write protected.
8.5.3 Trojans
Trojans are programs that appear to be desirable peices od software, however
they have the capacity to harm data. Unlike viruses they do not copy themselves
automatically.
