Worm
A self-contained program or set of programs, that spreads functional copies of itself or
its segments to other computer systems. Unlike viruses, worms do not need to attach
themselves to a host program, but spread through network connections.
Worms can be put in two categories:
| 1. |
Host
Computer Worms: they are in the computer they run on, using network connections to copy
themselves to other computers. They terminate themselves after being copied on another
host. |
| 2. |
Network Worms: they comprise
multiple parts/segments. Each segment runs on a different machine, performing different
actions. The network is used for several communication purposes, propagating a segment
from one machine to another being one of them. |
Trojan
Horse
A program meddles with the programmers' work but is not visible or documented. Trojan
Horses do not replicate, unlike viruses. In other words, it does not spread to other
programs. A virus could be considered to be a special case of a Trojan Horse.
Dropper
A program that is designed to install a virus onto a computer. It contains the virus code,
which cannot be detected by scanners. The dropper program itself is not infected with the
virus.
ANSI
Bomb
A sequence of characters that reprograms various keyboard functions of computers. It is
usually embedded in a text file. This happens in computers with ANSI console (screen and
keyboard) drivers.
ChipAway
Virus
The ChipAway virus, in fact, is not a virus!
In many PCs there is an advanced BIOS feature that, when activated, prevents any writes to
the MBR through BIOS disk routines. When active, this feature can cause problems if you
install non-DOS operating systems (like OS/2, Windows 95 or Windows NT). |
