11.1.2 Document the Company’s Security PoliciesPolicies are the foundation for everything that a security team does. Formalpolicies must be created in cooperation with people from many other departments. The human resources department needs to be involved in certainpolicies, especially in determining acceptable-use policies, monitoring andprivacy policies, and creating and implementing the remedies for any policybreach. The legal department should be involved in such policies as determining whether to track and prosecute intruders and deciding how and when toinvolve law enforcement when break-ins occur. Clearly, all policies need thesupport of upper management.The decisions the security team makes must be backed by policy to ensurethat the direction set by the management team is being followed in this verysensitive area. These policies must be documented and formally approved bythe appropriate people. The security team will be asked to justify its decisionsin many areas and must be able to make decisions with the confidence it is doing so in the best interests of the company, as determined by the managementof the company, not by the security, engineering, or any other group.Different places need different sets of policies, and, to some degree, thatset of policies will continually evolve and be added to as new situations arise.However, the following common policies are a good place to start in buildingyour repertoire.
• An acceptable use policy (AUP) identifies the legitimate users of the
computer and network resources and what they are permitted to use
those resources for. The AUP may also include some explicit examples
of unacceptable use. The legitimate users of the computer and network
11.1 The Basics 277
resources are required to sign a copy of this policy, acknowledging that
they have read and agreed to it before being given access to those resources. Multiple AUPs may be in place when a company has multiple
security zones.
• The monitoring and privacy policy describes the company’s monitoring
of its computer and network resources, including activity on individual computers, network traffic, email, web browsing, audit trails, and
log monitoring. Because monitoring may be considered an invasion of
privacy, this policy should explicitly state what, if any, expectations
of privacy an individual has while using these resources. Especially in
Europe, local laws may restrict what can and can not be in this policy.
Again, each individual should read and sign a copy of this policy before
getting access to the resources.
• The remote access policy should explain the risks associated with unauthorized people gaining access to the network, describe proper precautions for the individual’s “secret” information—password, personal
identification number (PIN), and so on—and provide a way to report
lost or stolen remote access tokens so that they can be disabled quickly.
This policy should also ask for some personal information—for example, shoe size and favorite color—through which people can be identified
over the telephone. Everyone should complete and sign a copy of this
policy before being granted remote access.
• The network connectivity policy describes how the company sets up network connections to another entity or some shared resources for access
by a third party. Every company will at some point want to establish
a business relationship with another company that requires closer network access and perhaps some shared resources: an extranet. You should
prepare in advance for this eventuality. The policy should be distributed
to all levels of management and stipulate that the security team be involved as early as possible. The policy should list the various forms of
connectivity and shared resources that are supported, which offices can
support third-party connections, and what types of connections they
can support.
• The log-retentionpolicy describes what is logged and for how long. Logs
are useful for tracking security incidents after the event but take up large
amounts of space if retained indefinitely. It is also important to know
whether logs for a certain date still exist if subpoenaed for a criminal
case.
278 Chapter 11 Security Policy
Case Study: Use Better Technology Means Less Policy
The easiest policy to follow is one that has been radically simplified. For example, password policies often include guidelines for creating acceptable passwords and specifying how often they need to be changed on various classes of machines. These details
can be reduced or removed with better technology. Bell Labs’ infrastructure includes a
secure handheld authenticator (HHA) system, which eliminates passwords altogether.
What could be simpler?
❖ Handheld Authenticators An HHA, a device the size of a small calculator or a fat credit card, is used to prove that people are who they
say they are. An HHA generates a one-time password (OTP) to identify
the user. One brand of HHA displays a new 7-digit number every 30
seconds. Clocks are synchronized such that the host knows what digits
should be displayed at a given time for a particular user. The user enters
the digits instead of a password. (The HHA is protected with a PIN.)
Therefore, the computer can know that the user is who she claims to be
or at least is holding the right HHA and knows the PIN for that person.
This is more secure than a password that never, or rarely, changes.
HHAs can be used to log in to hosts, gain secure access---UNIX su
command---and even gain access to web sites. With this infrastructure
in place, password policies, become much simpler. Hosts outside the
firewall no longer require password policies, because they don’t use
plain passwords. Gaining root access securely on UNIX systems, previously difficult because of paranoia over password sniffing, is made more
feasible by virtue of HHAs combined with encryption.1 This is an example of how increased security, done correctly, made the system more
convenient.
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