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Unit 13: Wireless Networks Security

DoS attacks can also target tangible system resources, such as computational resources Notes
(bandwidth, disk space, processor time); configuration information (routing information, etc.);
state information (for example, unsolicited TCP session resetting). Moreover, a DoS attack can
be designed to: execute malware that maxes out the processor, preventing usage; trigger errors
in machine microcode or sequencing of instructions, forcing the computer into an unstable state;
exploit operating system vulnerabilities to sap system resources; crash the operating system
altogether.
The overriding similarity in these examples is that, as a result of the successful Denial of Service
attack, the system in question does not respond as before, and service is either denied or severly
limited.

13.6.2 Distributed Denial of Service (DDoS) Attacks

A DDOS attack (better known as a Distributed Denial of Service attack) is a type of web attack
that seeks to disrupt the normal function of the targeted computer network. This is any type of
attack that attempts to make this computer resource unavailable to its users. While this type of
attack typically follows the same sorts of patterns, the definition of the term Distributed Denial
of Service does not make any specific indications of how this type of attack is to be pulled off.
What makes this type of attack "distributed" is the concerted efforts between a large number
of disruptors all for the common goal of preventing web servers (and therefore websites) from
functioning effectively at all. These users may be willing participants, or in some cases be tricked
into downloading software that will use their terminal to aid in the offensive. All in all, regardless
of the means, a DDOS attack is simply a combined effort to prevent computer systems from
working as well as they should, typically from a remote location over the internet.
The most common method of attack is to send a mass saturation of incessant requests for external
communication to the target. These systems are flooded with requests for information from non-
users, and often non-visitors to the website. The goal of this attack is to create a large enough
presence of false traffic such that legitimate web traffic intended for actual web users is slowed
down and delayed. If this type of service becomes too slow, time sensitive information such as
live video footage may be rendered entirely useless to legitimate end users.

For a DDOS to work effectively, the process has to be heavily automated on the attacker's end.
Customized software is designed to flood these services with false traffic, and is run on as many
computers as possible. There are a few instances in which this type of software was set up like
a virus, infecting computers and taking control of their communication functions. These users
unwillingly are aiding in a DDOS attack, sometimes without being the slightest bit aware of
it. If there seems to be large delays in normal internet service, there may be outbound requests
being made consuming your internet connections given throughput, and can sometimes be an
indication of foul play. Users seeking to limit this risk should keep anti-virus software up to date,
and scan frequently for these types of programs.
While there are few court cases on the books of Distributed Denial of Service perpetrators being
held accountable for their actions, as well as the potential lost income for commercial websites,
this type of activity almost always violates the terms of service and acceptable use policies of
internet service providers, as well as often violating individual communication law within the
nation. These types of attacks have become more and more prevalent as time goes on, and in
many nation legislation is in the works, with hopes of criminal penalties for those involved with
this sort of attack.
All in all, a DDOS attack is a very real threat to businesses and organizations across the world,
and it's important that they be prepared in case some group of people decides to cause trouble
for your organization. Being prepared to identify these types of threats is an important part of
proper internet use, and should be a part of your daily life online.

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