System information

Threats to computer security 27
TYPE
NAME
DESCRIPTION
Dos
Network attacks
Denial of Serive (DoS) programs send
numerous requests from the user's
computer to a remote server. The server
will then exhaust its resources for
processing requests, and will stop
functioning.
Exploit
Exploits
An exploit is a set of data, or a piece of
program code, which uses an application's
vulnerabilities to perform a malicious action
on the computer. For example, exploits can
write or read files, or access “infected” web
pages.
Different exploits use the vulnerabilities of
different applications or network services.
An exploit is transferred via the network to
multiple computers in the form of a network
packet, searching for computers with
vulnerable network services. For example,
an exploit contained in a DOC file looks for
vulnerabilities of text editors, and when the
user opens an infected file, can start
performing functions programmed by the
intruder. An exploit contained in an e-mail
message searches for vulnerabilities in e-
mail client programs; it can start performing
its malicious action as soon as the user
opens an infected message using this
program.
Exploits are also used to distribute net
worms (Net-Worm). Exploit-Nukers are
network packets that make computers
inoperative.
FileCryptors
File Cryptors
File cryptors encrypt other malicious
programs, to hide them from anti-virus
applications.