Education agencies thrust into the world of computer networks and
electronic communications are often unprepared for the related security
risks and are unaware of many of the strategies that can protect
their system. The agency's technology officers or technical staff
working directly with Internet or intranet (i.e., internal networks,
as opposed to the outside world of the Internet) networks will most
readily appreciate the technical aspects of security presented in
this chapter. Nontechnical staff should find the broader discussion
of security helpful in understanding the absolute necessity for
and value of securing all facets of the agency's network.
Security is a process that focuses
on ?CIA?: confidentiality, integrity, and availability.
The recommendations in this chapter are detailed and extensive.
Education agencies must be prepared for every eventuality ranging
from a careless employee walking away from a computer station
that is logged onto a sensitive data site to a hacker trying to
break into the agency's system to physical destruction of the
network by a tornado, hurricane, or earthquake. An agency involved
in maintaining a computer network, especially one with Internet
access, should use the information in this chapter to identify
and resolve system vulnerabilities and in so doing reduce the
risk of liability.
The security recommendations described in the chapter are solid,
fundamental business practices that are, for the most part, not
unique to the education sector. However, because education agencies
are responsible for ensuring the physical safety of children in
a stable environment that fosters learning, the obligation to
extend security precautions to online computer information systems
is especially strong. In addition to student safety, other areas
at potential risk include the confidentiality of student, staff,
or financial data sent or received through the Internet; the integrity
of intellectual property; and the investment in hardware, software,
and other resources.
When considering security precautions, education agencies in
particular should take note that the greatest exposure to risk
comes from within the organization. Internal agency employees
perpetrate most network security violations. Malicious, or even
unintentional, corruption of data, hardware, or software can be
crippling to any enterprise. Illegal acquisition and disclosure
of sensitive student information can harm a child and ultimately
the school system.
An agency should assess the legal
and financial ramifications of failing to make a reasonable
effort to secure the network and its many components.
The following key areas for strategic planning organize the
discussion of network security in this chapter. The following
methods for securing each component of the network, whether a
local or wide area network, are presented:
- security assessment;
- securing hardware;
- securing operating systems;
- securing software (applications);
- securing the network, including wireless networks; and
- data security.
The first question to ask is what needs to be done to provide
appropriate security for the agency's network? The total
network is only as secure as its weakest link, and, as mentioned,
most security breaches occur from people who work inside the agency
itself. For this reason, the implementation of very simple security
measures, many of which are free or are inexpensive, can provide
significant protection for the total network.
The first step is to perform a security assessment. If multiple
agencies are connected to a larger intranet (a private network
that provides users access within the agency and to the public
Internet), the security assessment is ideally performed collaboratively.
Common security strategies should be employed throughout this
intranet and for all components of the network.
In performing a security assessment, the agency should address
each of the topics discussed in this chapter. In assessing the
level of security, agency staff should
- identify each point of potential failure in the system and
assess how each failure would affect the agency;
- prioritize the points at greatest risk or those that would
cause the biggest problems for the agency; and
- ascertain one or more solutions to secure those points and
determine the costs associated with each solution.
A security plan should be written under the auspices of the district
technology director, but should involve other agency representatives.
When developing the plan, the agency should consider the following
- The plan should be drafted for adoption by the governing
- The plan should take into consideration the information gained
during the assessment phase.
- System users should be educated about the plan and its importance
to the agency.
- System users should be consistently informed of changes to
- The agency should regularly appraise security protocol and
should revise or update the plan as needed.
Hardware security includes the physical protection of equipment
(e.g., computers, printers, monitors, etc.) from both theft and
damage. Different types of hardware require different types of protection.
Servers and related equipment should be placed in a secure room
with limited access. The room should have proper environmental conditioning
and fire protection equipment.*
fire extinguishing systems should be used in areas where water cannot
While this may seem obvious, an asset (inventory) control system
will assist with the agency's technology planning efforts. Without
an asset control system, the agency will be unable to determine
what hardware exists or where it is. This system is also important
so that the agency can determine which computers, or other systems,
need to be replaced as they become obsolete.
Along with the obvious fact that proper security deters theft
of property, effective hardware security bars unauthorized access
to the server. Proper security prevents people from tampering
with server settings, corrupting data, or gaining access to unauthorized
programs and confidential information. Measures for securing hardware
systems include the following:
- allocate dedicated building space to house centralized hardware;
- maintain controlled entry (e.g., card, key, combination lock
- make certain that a proper fire protection system exists;
- maintain proper temperature and humidity controls;
- evaluate the need for adequate electrical power, including
power for air conditioning;
- provide emergency sources of power (e.g., UPS battery backup,
alternative electrical generator);
- arrange equipment placement within equipment racks and on
the floor in a way that allows adequate ventilation;
- monitor the room environment and electrical systems; and
- use network monitoring and packet-sniffing (see below)
utilities that display and log data traffic to detect the installation
of unauthorized hardware and/or software applications (i.e.,
monitor for protocol violations, bandwidth-intensive applications,
Securing Operating Systems
The operating system (OS) is the underlying computer system
on which application programs run. Choosing an OS is a critical
decision that directly affects the security measures an agency
must take. Some OSs are easy to use but less secure. Others are
more complicated to maintain but when properly configured are
virtually impenetrable. Whatever the choice, the system must be
"hardened," or secured, by removing unneeded functions, restricting
access, and tracking changes and processes.
If, for example, a port (i.e., a doorway into a system) is left
open unintentionally, it can become the door through which an
intruder can enter the network. Conversely, if the system is secure,
intruders will have a much more difficult time entering the system.
Many OS options are available, from "UNIX-like" freeware (public
domain software offered at no cost) to various Microsoft and
Apple products, which vary in acquisition and maintenance costs.
Acquisition cost does not necessarily indicate the power of any
particular OS. The agency should ensure that the hardware and
OS combination is robust enough for the intended purpose. The
OS must have the ability to be configured to meet both the service
and security requirements of the agency.
The criteria for the OS selection should be based on the agency's
needs assessment. The agency should take into account the resources
necessary to support the OS. If the agency chooses to run a
mixed environment (a combination of hardware and software
utilizing more than one OS), it should be sure the support resources
required to maintain this configuration are available. A mixed
computing environment requires additional expertise and resources
in order to maintain proper security.
OS security consists of limiting access to network resources,
such as centralized applications, files and directories, network
printers, and other such components. Personnel should have network
access only for the specific tasks related to their work. An appropriate
policy for OS security is a baseline denial of access to all components
by all personnel, with explicit access privileges granted on a
case-by-case basis. User login credentials identifying the role(s)
and profile of the user should "describe" the user's access parameters
to the OS. The extent of access to network resources granted to
the user should be based on the individual's authorized role/profile.
Different operating systems regulate user access in different
ways; however, each provides similar functionality by assigning
Read, Write, and Execute permissions on directories, files, network
printers, etc., to groups of users or individual users as required.
Some access-related security measures that should be implemented
are as follows:
- disable guest accounts;
- change default passwords;
- force frequent user password changes;
- allow only nondictionary passwords, that is, a combination
of alpha and numeric characters;
- deny access by default;
- restrict off-hour access unless the user requires 24/7 access;
- for ease of administration, control access based on groups,
profiles, and policies;
- assign users into the smallest possible groups to eliminate
- designate a system administrator backup to adequately cover
- require administrator access through a different login mechanism,
not through the normal user login;
- allow only needed services to run on the network (e.g., Telnet,
web, RSH, FTP, NTP, etc.);
- allow only authorized administrators to install software;
- allow only needed protocols to run on the network (e.g.,
IPX/SPX, Appletalk, NetBEUI, TCP/IP, DLC, SNMP, etc.);
- integrate TACACS+ or RADIUS authentication into the agency's
firewall to avoid unauthorized Internet access; and
- enable firewall, virus, intruder detection, and network monitoring
software (see below).
Securing Software (Applications)
As noted earlier, software programs are applications that run
"on top" of the operating system. The most common applications
are information systems, word processors, spreadsheets, e-mail
programs, and web browsers. There are literally thousands of applications
available. The purpose of this section is to provide education
agencies with recommendations for securing software applications.
Security in this area will limit (not eliminate) copyright infringements,
assist in the proper licensing of software, and attempt to ensure
that only authorized persons have access to software installation
Software installation media should be stored in a centralized
location with proper documentation of the number of licenses and
number of installations. These media should be protected from
harsh environmental conditions, such as excessive heat, moisture,
and electrical and magnetic fields (EMF).
All software media should be backed up regularly to ensure that
no data are lost. Periodic backups stored in a secure off-site
location will make it possible to recover quickly from a catastrophe
on site. The agency should take into account regional peculiarities
when storing backups off site. For example, in areas prone to
earthquakes, media should not be stored in high-rise buildings;
in areas prone to flooding, media should be stored in a facility
away from the flood plain.
Some recommendations for software security are as follows:
- store software media in a locked cabinet within a proper
- retain off-site storage for backups of installation media;
- test the process for restoring software;
- retain off-site storage of licensing and application documentation;
- maintain and back up licensing management and related documentation;
- allow access to applications through the use of network security
settings to only those groups/users that require access;
- implement a software-auditing package to ensure license compliance
and to ensure that no unauthorized software has been installed
on the agency's system;
- standardize applications across the agency;
- use virus-scanning software with frequent definition updates
(network-attached appliances are available for e-mail virus
- use spamming prevention or filtering software to prevent
unauthorized entry of email (e.g., do not allow web-based e-mail
programs, such as Hotmail?). Unauthorized e-mail entry is a
serious vulnerability that can lead to the entry of viruses
into the network through a "back door."
Securing the Network
The same security procedures in place for server hardware apply
to equipment that supports the network, including switches, hubs,
routers, firewalls, access points, cabling, etc. Network equipment
should be installed in an environment with proper ventilation and
power requirements and should be protected from unauthorized access.
The agency should place the equipment in dedicated building spaces.
Access should be limited to staff that have a key, combination lock,
key card, or other security device. Some basic precautions for securing
network equipment are as follows:
- limit access to network equipment to authorized individuals;
- do not allow users to install unauthorized network equipment;
- use secure, encrypted passwords for "root" access (access
to the "root" enables users to control entire systems or servers);
- ensure proper cabling and cable protection by
- running cabling under a false floor,
- avoiding running cable over fluorescent lighting fixtures,
- staying within cable/fiber length requirements.
A fundamental action the agency can take toward maintaining a secure
and reliable network is to hire a qualified individual to serve
as the network administrator. Network administration is not a task
for the average high school teacher/technology coordinator. Many
agencies, however, cannot afford to hire an experienced network
administrator for each school and often do rely on faculty for this
position. If a teacher/coordinator is to be responsible for a school
network, the agency must recognize training and professional development
Agency network policies and procedures should be clearly defined.
These policies should be made readily available to anyone responsible
for maintaining the network. Listed below are some items to consider
for agencies managing their own networks. The responsibilities
of a network administrator are, for the most part, very technical
in nature. This reinforces the point that training is critical
for anyone with the responsibility of running a network. Agencies
- assign one individual to be responsible for network administration
(and one individual as his/her backup);
- limit access to network equipment console screens by login
credentials (either on the piece of network equipment or using
an authentication server);
- limit access to Telnet sessions on network equipment through
access lists and/or authorized workstations where only authorized
users have access;
- limit protocols running on the network equipment;
- configure login banners to warn intruders of possible prosecution;
- use firewalls to prevent unauthorized access between external
and internal systems;
- use unroutable IP addressing schemes within the internal
network [Class A - 10.0.0.0-10.255.255.255 (10/8 prefix), Class
B - 172.16.0.0-172.31.255.255 (172.16/12 prefix), Class C -
192.168.0.0-192.168.255.255 (192.168/16 prefix)];
- utilize intrusion detection systems (IDS);
- inspect, analyze, and maintain router audit logs;
- provide ingress and egress access control list (ACL) filtering
to prevent IP spoofing; and
- eliminate unauthorized network resource use by
- monitoring network traffic and bandwidth usage and protocols
to ensure adequate bandwidth for applications;
- removing the ability to download unauthorized files;
- restricting remote access to network resources to authorized
individuals with types of remote access including dial-up
connections, virtual private networks (VPN), and Point-to-Point
- implementing a multiple-authentication policy for authorized
users or integrating into an authentication server;
- eliminating any "back-door" types of equipment (e.g.,
user modems installed on desktops);
- maintaining proper encryption of remote connections to
ensure confidentiality; and
- using VPN technology with proper encryption to gain connectivity
through the public networks such as the Internet.
Wireless communication is a rapidly evolving technology that is
becoming increasingly prevalent in everyday life. The built-in security
for wireless computer networks, however, is relatively weak. Technology
coordinators need to pay particular attention to secure these networks
properly, and the network administrator must keep up to date on
emerging methods for securing wireless networks. Some security measures
to consider when planning a wireless network are as follows:
- shut off Service Set Identifier (SSID) broadcasting and use
an SSID that does not identify the agency by name;
- select a hardware vendor and software revision that has fixed
the problem of randomization of initialization vectors (IVs);
- utilize applications like AirSnort or BSD-AirTools, which
will be less likely to crack the agency's Wired Equivalent Privacy
- use 128-bit WEP and change WEP keys regularly. Select a vendor
that provides a tool to rotate the agency's WEP keys;
- disallow access to resources at the first router hop other
than the agency's VPN server, which ensures that the only host
available to the wireless segment is the VPN server until a
tunnel is established;
- place wireless access points on a dedicated virtual local
area network (VLAN). Do not mix wired and wireless clients
on the same LAN segment;
- implement a policy that limits the amount of connectivity
a wireless client has to the agency's network. Assess whether
students/faculty/staff need more access than TCP/80, TCP/443,
- utilize personal firewalls on the agency's workstations;
- disable automatic IP address assignment (DCHP).
If hackers are able to guess or crack the agency's WEP keys, they
will not be able to access the remainder of the internal network
because VPN and VLAN architecture with access lists will allow only
authorized VPN clients to be routed to the network from a wireless
VLAN segment. Hackers will be able to attack clients on the same
subnet, however, and if one VPN connection is left up, it could
be abused to access the rest of the internal network.
Reliability of the network is a key to daily business operations
and to an effective instructional program. Everyone in the school
hears about the times a teacher has scheduled a web-dependent
lesson only to be unable to access the network. It is imperative
that "mission-critical" applications (e.g., financial systems,
student information systems) always be available to those who
depend on the systems.
Network architecture designed for redundancy, with built-in
backups for primary resources, minimizes the incidence of network
downtime. When considering this issue, the agency should take
into account the extent of redundancy needed.
Where it is possible, consider redundancy in both LAN and wide
area network (WAN) architectures during the design phase. The
agency should select redundant service providers that use separate
infrastructures. Some specific redundancies that can be built
into the network apply to
- the local loop for WAN connectivity;
- switch management modules with redundant connections;
- power sources for network equipment backed up by monitored
- power supplies in network equipment;
- network management (supervisor) modules in network equipment;
- cabling, as required; and
- redundant cabling in redundant conduits, ducts, or poles.
Having a second cable running through the same conduit as the
first provides little protection. For example, a conduit could
be dug up by an "uncaring" backhoe destroying both primary and
Another measure to maximize network reliability is the implementation
of intrusion detection systems. Intrusion detection systems are
host-based or network-based software that monitors attempts to break
into and gain access to the network. These systems watch data packets
as they transit the network outside the firewall. They monitor attempted
port scans, distributed denial of service (DoS) attacks, and other
intrusion attempts. Intrusion detection protocol should include
the following tasks:
- install and configure an intrusion detection system;
- enable port monitoring outside the agency's firewall;
- review intrusion detection system log files daily;
- configure blocking on the router (e.g., "black hole routing"
of unwanted data) to head off severe hacking attempts; and
- contact the organization that owns the address of the attacking
IP address. Tools such as nslookup, tracerroute,or the following
web sites can help identify the owners of the IP address space
from which an attack originated:
Data drive the engine of each educational organization. From
payroll records to "datadriven decisions" about instructional
programs to student information systems, human resources files,
transportation information, and student portfolios-data integrity
Keeping data secure is the primary mission of those in charge
of technology. Protecting the agency's data by implementing robust
architectures and comprehensive backup and recovery plans is extremely
important. The agency must take every precaution to prevent unauthorized
users from changing data, deliberately or inadvertently, by way
of a "hole" in security procedures. Security holes can occur from
outside through the web or internally from within the LAN.
The following recommendations for maintaining data security
are based on using Redundant Array of Independent Disks (RAID).
This allows the same data to be stored in different places on
multiple hard drives. When using RAID, the following steps should
- Data files should be stored on separate logical drives consisting
of a RAID-5 (stripped set) array of physical devices.
- Transaction logs should be stored on, at least, a RAID-1
- Applications should be installed on either a mirror set (RAID-1)
or stripped set (RAID-5) and should be backed up when installed,
changed, or updated.
- Operating systems (OS) should be installed on, at least,
a RAID-1 array and be backed up when they are changed.
- OS, applications, and data should be stored on separate physical
and logical drives (e.g., mirror set 0 to contain the system,
mirror or stripped set 1 to contain applications, stripped set
2 to contain data).
- Consistent backups of data off site should be maintained.
- Robust network-attached storage (RAID-5) or storage area
networks to maintain online or backup data should be used.
- Clustered server architecture should be considered if the
information stored is "mission critical.
Backing up Data
The reasons for backing up data are obvious. However, many agencies
(both inside and outside the education community) do not take this
task seriously until they lose data. When the payroll information
cannot be found or when all the student information entered into
the system during the day is lost, people will pay attention to
backing up data. It is better to pay attention before a disaster