The managers of divisions or computer sites develop the detailed
security policy. It is a written set of guidelines on the use of
passwords and system accounts, physical access to the computer systems, communication
devices, and computer terminals, and the types of security-relevant
events to audit. These security guidelines might be followed by
more specific statements applying to particular operating system enviroments.
The complexity of a security policy eventually depends on
whether the division has high, medium, or low security requirements.
Understanding System SecurityChapter 1 provides
a set of questions that can help an organization determine its needs.
As an example, a site security policy often defines which
company employees have access to certain systems and the type of
access available to the personnel performing nonroutine tasks and
development. Sometimes a policy can provide an intricate set of
rules for determining system access.
Example of a Site Security Policy presents the policy developed by one division.
Table 1 Example of a Site Security Policy
|
Security Area |
Site Requirements |
Passwords
|
Schedule for password changes.
|
|
Process for controlling
minimum password length and expiration periods.
|
|
Schedule for system password
changes.
|
Accounts
|
Procedure to grant accounts
on computer systems, for example, statement of need, signature of
requester, requester's manager, system manager, or person setting
up the account. (Accounts can never be shared.)
|
|
Procedure to deactivate
accounts due to organizational changes, for example, employee transfers
or terminations.
|
|
Timetable for reauthorizing
accounts, usually once every 6 to 12 months.
|
|
Directive to deactivate
accounts that are not used on a regular basis.
|
|
Time periods for access.
|
|
Timetable for expiring accounts.
|
|
Procedure for requesting
privileges that rigorously controls allocation.
|
|
Requirement to use nonprivileged
accounts for privileged users performing normal system activity.
|
|
Schedule for verifying inactive
accounts.
|
|
List of approved security
tools.
|
Security events
to audit
|
Logins from selected or
all sources.
|
|
Changes to authorization
file records.
|
|
Other uses of privilege
and system management actions.
|
|
Modifications to the known
file list through the Install utility.
|
|
Modification to the network
configuration database, using the network control program (NCP).
|
Physical access
to the computer room
|
A written list of authorized
personnel with the reason for access included. Typically, one person
would be responsible for keeping this list current.
|
|
Storage of a visitor log
in a secure area.
|
|
Locked access doors and
a documented procedure for assigning keys, key cards, and combinations.
(These access controls change periodically and on transfer or termination
of employees.)
|
Physical access
to terminals and personal computers located outside the computer
room
|
Use of programs to log out
terminals that have not been used for a given period of time.
|
|
Security awareness programs
for the organization (beyond computer personnel); topics may include: - Maintaining a list of approved software.

- Keeping desktops clear of hardcopy information relating
to the computer system, network passwords, and other system account
information.

- Locking disks and file cabinets.

- Keeping diskettes inaccessible in or near workstations.

- Keeping keys out of open view.
|
Dialup numbers
|
List of authorized users.
|
|
Schedule for changing numbers
periodically and procedures for notifying users of number changes.
|
|
A policy to minimize publishing
dialup numbers.
|
|
Policy about changing passwords
periodically and when employees with access are terminated.
|
|
Password protection, either
in the modems or terminal servers, or system passwords on host dialup
ports.
|
|
Documentation available
about: - A dial-back system

- Details about the network

- Terminal equipment installed

- Terminal switching systems

- Details about all terminal devices connected to
the network

- Details about all dialup equipment
|
Communications
|
Denial of access into privileged
accounts if using passwords over TCP/IP, LAT, or Ethernet links.
|
|
Use of authentication cards for network
logins into privileged accounts.
|