| An organization's information is one of
its most valuable assets. Network security is becoming increasingly
important as networks become larger and more complex. Today's mobile
and telecommuting users require access locally as well as from outside
the network. Threats to an organization's resources can come from
internal as well as external sources. Information theft and
destruction as well as resource access denial are real concerns for
users and system administrators. The overall goal of any information
security system is to ensure that information is accurate and
available where and when needed. There are a number of components that
must interact in a comprehensive network security policy.
Physical Access Security - The
first line of defense locally to protect network equipment such as
servers, switches, and routers is to keep them in a locked, climate
controlled, fire protected environment. If equipment is not physically
accessible to unauthorized personnel, there is less chance of
accidental or intentional tampering.
Login / Password Security -
Login and password security require that any user accessing a
workstation or server have a valid login ID and password. UNIX has
specific requirements for creating and changing passwords. The system
administrator can also require that passwords be changed periodically.
Setting screen savers that time out and activate your workstation lock
are additional measures that enhance login security.
File Systems Security - A major
component in any comprehensive security policy, file system security
determines who can get to what data and what they can do with it.
System administrators set up file system security based on users,
groups, and permissions.
Virus protection - Viruses can
do tremendous damage to individual workstations and network servers.
Many network operating systems and workstations require anti-virus
software for adequate protection. UNIX is susceptible to virus attacks
like other operating systems, but most viruses are written for Windows
based systems because they can affect more systems faster. In
addition, most virus creators are not familiar with the UNIX
environment enough to know how to create a "UNIX" virus.
Remote Access Security - With
increases in telecommuting, the network must allow legitimate users to
access resources remotely while protecting them from unauthorized
access. Access servers and software provide this function.
Internet Firewalls -
Organizations that maintain Internet web sites need protection from
hackers. Various software and hardware solutions are available to help
ensure that web servers are available to provide services to
legitimate users.
Data backups - A comprehensive
security policy must include regular backups of important data to
minimize downtime in the event of a security breach or disaster such
as fire or flood. Backup media such as tapes should be kept offsite in
a climate controlled secure environment. Test restores of data should
be performed periodically to ensure that data can be recovered from
the backups.
Disaster Recovery Plan - A
written plan that identifies critical data and documents by functional
department within an organization. It describes protective measures
and steps necessary to ensure that the organization can continue to
operate and get back to business quickly with minimum impact to
customers.
Audits - Security audits should
be performed periodically to ensure that the organization and its
users are following the security policy and preparing adequately for
disaster recovery. Security Audit tools are also available for system
administrators to analyze and detect security loopholes such as files
with open permissions.
The primary function of system security
is to deny access to unauthorized users. Keeping computer information
secure is important to the user and the system administrator. By
protecting their files and accounts from unauthorized use, users are
also protecting their job and reputation. Standard UNIX environment
security features include:
- user passwords that restrict access
to the system
- file and directory protection with
permissions
- files that control remote logins and
commands on individual workstations
- other features that enable system
administrators to check for security breaches.
UNIX operating systems have two
default levels of security. First, users must supply a login ID and
password in order to access a UNIX workstation or server. Second,
files and directories are automatically protected by permissions when
they are created.
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Interactive
Media Activity
(Flash,
95 kB) |
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Security
Policy Exercise
In
this drag-and-drop media activity, you are to drag
the term on the left of the graphic to match the appropriate
definition listed on the right.
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