HP SuperStack Firewall Series Manual do Utilizador descarregar pdf (Página 175)

YPES OF

TTACK AND

IREWALL

EFENCES

This chapter describes the some of attacks that hackers may use to

infiltrate and attack your network. It also details the way in which the

Firewall will counter the attacks. The following sections are covered in this

chapter:

■

Denial of Service Attacks

■

Intrusion Attacks

■

Trojan Horse Attacks

Denial of Service

Attacks

Denial of Service (DoS) attacks are malicious attacks designed to cause

harm. The consequences of an attack range from the loss of few seconds

of time on a web server or network to the crash of a server. In the worst

case the attacker can learn enough about your company infrastructure

and exploit its vulnerabilities to crash any server at will.

Denial of Service attacks work by exploiting weaknesses in TCP/IP,

exploiting weaknesses in your servers or by generating large amounts of

traffic (brute force attacks). Commonly attempted attacks and the

reaction of the SuperStack

3 Firewall are listed below.

Ping of Death A ping of death attack attempts to crash your system by sending a

fragmented packet which, when reconstructed is larger than the

maximum allowable size. Other known variants of the ping of death

include teardrop, bonk and nestea.

Firewall Response: Packet is dropped. Attack is stopped.

Smurf Attack A smurf attack involves two systems. The attacker sends a packet

containing a ICMP echo request (ping) to the network address of one

system. This system is known as the amplifier.

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HP SuperStack Firewall Series Manual do Utilizador Página 175