To protect your systems completely, you must first recognize
who or what you’re protecting them from. What typically comes to mind when
discussing network security is protecting the network from mysterious hackers
operating from a dark room full of sophisticated computer systems. This is
rarely the case. According to the FBI, up to 80 percent (1999) of all security
breaches reported are from internal sources. Internal security threats range
from a novice server administrator or user who unknowingly installs software or
opens an e-mail attachment to a disgruntled employee who attempts to delete
source code from a development server.
To prepare for and defend against threats properly, you must first
understand the types of threats to your network security. Four basic network
security threats exist.
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Internal threats
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External threats
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Unstructured threats
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Structured threats
Internal
Threats
The term “internal attack” is used to describe an attack
being implemented from a person or organization with some level of authorized
access on your network. Internal attacks are performed from within the trusted
area of the network. This type of threat can be more difficult to defend against
because employees already have access to the network and private company data.
To compound the internal threat further, most companies only have firewalls at
the edge of their networks, and they rely strictly on access control lists (ACL)
and server permission to regulate internal security. Server permissions
typically protect resources located on the local servers, but provide little or
no protection for the network. Internal threats are typically executed by
disgruntled employee(s) who want to “get back” at the company.
Many, if not all, of the security measures are logically connected
to the perimeter of the network, protecting the inside networks from the
external connections, such as the Internet. While the perimeter of the network
is secured, the inside or trusted portion of the network tends to be soft. Once
an intruder has made it through the hard outer shell of the network,
compromising one system after another is usually simple.
Wireless networks introduce a new area of concern for
Security Administrators. Unlike cabled networks, wireless networks create a
realm of coverage that can be intercepted and used by anyone with the right
software and a wireless network adapter. Not only can all network data be viewed
and recorded, but network attacks can also be launched from inside the network
where the infrastructure is much more vulnerable. Because of the severe security
implications, strong encryption should always be used with wireless
networks.
External
Threats
External threats are posed by any organization, government,
or individual that attempts to gain access from outside the company’s network
and includes anyone that doesn’t have authorized access to the internal network.
Typically, external attackers attempt to gain access from dialup servers or
Internet connections. External threats are what companies spend the most time
and money trying to prevent.
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External threats are from anyone that doesn’t have
authorized access on the internal network.
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Unstructured
Threats
Unstructured threats are the most
prevalent threats to a company’s system infrastructure. Novice hackers, commonly
called script kiddies, download software developed by more
advanced hackers and use this software to gain information, access, or perform a
DoS attack against a target system or company. Script kiddies rely on the
software and experience of the more advanced hackers.
While script kiddies don’t have much experience or knowledge,
they can wreak havoc on an unsuspecting and/or unprepared company. What kiddies
lack in sophistication, they make up for in shear numbers. While this might seem
like a game to the kiddies, the companies that fall prey to these basic attacks
stand to lose millions of dollars, as well as the public’s trust. If a company’s
web server is broken into and defaced, the public believes hackers have
successfully broken through the companies’ security, when hackers have only
hacked into one vulnerable server. Web, FTP, SMTP, and any other servers
offering services on the Internet are all much more vulnerable to attack, while
more important and mission-critical servers reside behind multiple levels of
security. The general public doesn’t understand that breaking into a company web
site is much easier than cracking the company’s credit card database. The public
has to trust that a company is competent in securing its private
information.
Structured
Threats
Structured threats are the hardest to
prevent and defend against because they come from organizations or individuals
that use some sort of methodology to gain unauthorized access. Intelligence
organizations, organized crime, and governments are the potential backers of a
structured threat. Hackers with advanced knowledge, experience, and equipment
make up structured threats.
Experienced hackers understand how packets are formed and can
develop code to exploit vulnerabilities within the protocol structure.
Organizations or individuals that perform structured attacks are also aware of
the countermeasures used to prevent unauthorized access, as well as the IDS
systems and how they detect intruders. They know methods of evading those
protective measures. These highly motivated and technically competent intruders
can create customized code, use existing tools, or even modify existing
applications to perform according to their methodology.
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In some cases, a structured attack is performed by or with
the assistance of someone on the inside. This is referred to as a structured internal threat. Structured and unstructured
threats can be either internal threats or external threats. |