Network Working Group R. Pethia
Request for Comments: 1281 Software Engineering Institute
S. Crocker
Trusted Information Systems, Inc.
B. Fraser
Software Engineering Institute
November 1991
Guidelines for the Secure Operation of the Internet
Status of this Memo
This memo provides information for the Internet community. It does
not specify an Internet standard. Distribution of this memo is
unlimited.
Preamble
The purpose of this document is to provide a set of guidelines to aid
in the secure operation of the Internet. During its history, the
Internet has grown significantly and is now quite diverse. Its
participants include government institutions and agencies, academic
and research institutions, commercial network and electronic mail
carriers, non-profit research centers and an increasing array of
industrial organizations who are primarily users of the technology.
Despite this dramatic growth, the system is still operated on a
purely collaborative basis. Each participating network takes
responsibility for its own operation. Service providers, private
network operators, users and vendors all cooperate to keep the system
functioning.
It is important to recognize that the voluntary nature of the
Internet system is both its strength and, perhaps, its most fragile
aspect. Rules of operation, like the rules of etiquette, are
voluntary and, largely, unenforceable, except where they happen to
coincide with national laws, violation of which can lead to
prosecution. A common set of rules for the successful and
increasingly secure operation of the Internet can, at best, be
voluntary, since the laws of various countries are not uniform
regarding data networking. Indeed, the guidelines outlined below
also can be only voluntary. However, since joining the Internet is
optional, it is also fair to argue that any Internet rules of
behavior are part of the bargain for joining and that failure to
observe them, apart from any legal infrastructure available, are
grounds for sanctions.
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RFC 1281 Guidelines for the Secure Operation November 1991
Introduction
These guidelines address the entire Internet community, consisting of
users, hosts, local, regional, domestic and international backbone
networks, and vendors who supply operating systems, routers, network
management tools, workstations and other network components.
Security is understood to include protection of the privacy of
information, protection of information against unauthorized
modification, protection of systems against denial of service, and
protection of systems against unauthorized access.
These guidelines encompass six main points. These points are
repeated and elaborated in the next section. In addition, a
bibliography of computer and network related references has been
provided at the end of this document for use by the reader.
Security Guidelines
(1) Users are individually responsible for understanding and
respecting the security policies of the systems (computers and
networks) they are using. Users are individually accountable
for their own behavior.
(2) Users have a responsibility to employ available security
mechanisms and procedures for protecting their own data. They
also have a responsibility for assisting in the protection of
the systems they use.
(3) Computer and network service providers are responsible for
maintaining the security of the systems they operate. They are
further responsible for notifying users of their security
policies and any changes to these policies.
(4) Vendors and system developers are responsible for providing
systems which are sound and which embody adequate security
controls.
(5) Users, service providers, and hardware and software vendors are
responsible for cooperating to provide security.
(6) Technical improvements in Internet security protocols should be
sought on a continuing basis. At the same time, personnel
developing new protocols, hardware or software for the Internet
are expected to include security considerations as part of the
design and development process.
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RFC 1281 Guidelines for the Secure Operation November 1991
Elaboration
(1) Users are individually responsible for understanding and
respecting the security policies of the systems (computers and
networks) they are using. Users are individually accountable
for their own behavior.
Users are responsible for their own behavior. Weaknesses in
the security of a system are not a license to penetrate or
abuse a system. Users are expected to be aware of the security
policies of computers and networks which they access and to
adhere to these policies. One clear consequence of this
guideline is that unauthorized access to a computer or use of a
network is explicitly a violation of Internet rules of conduct,
no matter how weak the protection of those computers or networks.
There is growing international attention to legal prohibition
against unauthorized access to computer systems, and several
countries have recently passed legislation that addresses the
area (e.g., United Kingdom, Australia). In the United States,
the Computer Fraud and Abuse Act of 1986, Title 18 U.S.C.
section 1030 makes it a crime, in certain situations, to access
a Federal interest computer (federal government computers,
financial institution computers, and a computer which is one of
two or more computers used in committing the offense, not all of
which are located in the same state) without authorization.
Most of the 50 states in the U.S have similar laws.
Another aspect of this part of the policy is that users are
individually responsible for all use of resources assigned to
them, and hence sharing of accounts and access to resources is
strongly discouraged. However, since access to resources is
assigned by individual sites and network operators, the
specific rules governing sharing of accounts and protection of
access is necessarily a local matter.
(2) Users have a responsibility to employ available security
mechanisms and procedures for protecting their own data. They
also have a responsibility for assisting in the protection of
the systems they use.
Users are expected to handle account privileges in a
responsible manner and to follow site procedures for the
security of their data as well as that of the system. For
systems which rely upon password protection, users should
select good passwords and periodically change them. Proper
use of file protection mechanisms (e.g., access control lists)
so as to define and maintain appropriate file access control
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RFC 1281 Guidelines for the Secure Operation November 1991
is also part of this responsibility.
(3) Computer and network service providers are responsible for
maintaining the security of the systems they operate. They are
further responsible for notifying users of their security
policies and any changes to these policies.
A computer or network service provider may manage resources on
behalf of users within an organization (e.g., provision of
network and computer services with a university) or it may
provide services to a larger, external community (e.g., a
regional network provider). These resources may include host
computers employed by users, routers, terminal servers, personal
computers or other devices that have access to the Internet.
Because the Internet itself is neither centrally managed nor
operated, responsibility for security rests with the owners and
operators of the subscriber components of the Internet.
Moreover, even if there were a central authority for this
infrastructure, security necessarily is the responsibility of
the owners and operators of the systems which are the primary
data and processing resources of the Internet.
There are tradeoffs between stringent security measures at a
site and ease of use of systems (e.g., stringent security
measures may complicate user access to the Internet). If a site
elects to operate an unprotected, open system, it may be
providing a platform for attacks on other Internet hosts while
concealing the attacker's identity. Sites which do operate
open systems are nonetheless responsible for the behavior of
the systems' users and should be prepared to render assistance
to other sites when needed. Whenever possible, sites should
try to ensure authenticated Internet access. The readers are
directed to appendix A for a brief descriptive list of elements
of good security.
Sites (including network service providers) are encouraged to
develop security policies. These policies should be clearly
communicated to users and subscribers. The Site Security
Handbook (FYI 8, RFC 1244) provides useful information and
guidance on developing good security policies and procedures
at both the site and network level.
(4) Vendors and system developers are responsible for providing
systems which are sound and which embody adequate security
controls.
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A vendor or system developer should evaluate each system in
terms of security controls prior to the introduction of the
system into the Internet community. Each product (whether
offered for sale or freely distributed) should describe the
security features it incorporates.
Vendors and system developers have an obligation to repair
flaws in the security relevant portions of the systems they
sell (or freely provide) for use in the Internet. They are
expected to cooperate with the Internet community in
establishing mechanisms for the reporting of security flaws and
in making security-related fixes available to the community in
a timely fashion.
(5) Users, service providers, and hardware and software vendors are
responsible for cooperating to provide security.
The Internet is a cooperative venture. The culture and
practice in the Internet is to render assistance in security
matters to other sites and networks. Each site is expected to
notify other sites if it detects a penetration in progress at
the other sites, and all sites are expected to help one another
respond to security violations. This assistance may include
tracing connections, tracking violators and assisting law
enforcement efforts.
There is a growing appreciation within the Internet community
that security violators should be identified and held
accountable. This means that once a violation has been detected,
sites are encouraged to cooperate in finding the violator and
assisting in enforcement efforts. It is recognized that many
sites will face a trade-off between securing their sites as
rapidly as possible versus leaving their site open in the hopes
of identifying the violator. Sites will also be faced with the
dilemma of limiting the knowledge of a penetration versus
exposing the fact that a penetration has occurred. This policy
does not dictate that a site must expose either its system or
its reputation if it decides not to, but sites are encouraged
to render as much assistance as they can.
(6) Technical improvements in Internet security protocols should be
sought on a continuing basis. At the same time, personnel
developing new protocols, hardware or software for the Internet
are expected to include security considerations as part of the
design and development process.
The points discussed above are all administrative in nature,
but technical advances are also important. Existing protocols
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RFC 1281 Guidelines for the Secure Operation November 1991
and operating systems do not provide the level of security that
is desired and feasible today. Three types of advances are
encouraged:
(a) Improvements should be made in the basic security
mechanisms already in place. Password security is
generally poor throughout the Internet and can be
improved markedly through the use of tools to administer
password assignment and through the use of better
authentication technology. At the same time, the
Internet user population is expanding to include a
larger percentage of technically unsophisticated users.
Security defaults on delivered systems and the controls
for administering security must be geared to this growing
population.
(b) Security extensions to the protocol suite are needed.
Candidate protocols which should be augmented to improve
security include network management, routing, file
transfer, telnet, and mail.
(c) The design and implementation of operating systems should
be improved to place more emphasis on security and pay
more attention to the quality of the implementation of
security within systems on the Internet.
APPENDIX A
Five areas should be addressed in improving local security:
(1) There must be a clear statement of the local security policy,
and this policy must be communicated to the users and other
relevant parties. The policy should be on file and available
to users at all times, and should be communicated to users as
part of providing access to the system.
(2) Adequate security controls must be implemented. At a minimum,
this means controlling access to systems via passwords,
instituting sound password management, and configuring the
system to protect itself and the information within it.
(3) There must be a capability to monitor security compliance and
respond to incidents involving violation of security. Logs of
logins, attempted logins, and other security-relevant events
are strongly advised, as well as regular audit of these logs.
Also recommended is a capability to trace connections and other
events in response to penetrations. However, it is important
for service providers to have a well thought out and published
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policy about what information they gather, who has access to it
and for what purposes. Maintaining the privacy of network
users should be kept in mind when developing such a policy.
(4) There must be an established chain of communication and control
to handle security matters. A responsible person should be
identified as the security contact. The means for reaching the
security contact should be made known to all users and should
be registered in public directories, and it should be easy for
computer emergency response centers to find contact information
at any time.
The security contact should be familiar with the technology and
configuration of all systems at the site or should be able to
get in touch with those who have this knowledge at any time.
Likewise, the security contact should be pre-authorized to make
a best effort to deal with a security incident, or should be
able to contact those with the authority at any time.
(5) Sites and networks which are notified of security incidents
should respond in a timely and effective manner. In the case
of penetrations or other violations, sites and networks should
allocate resources and capabilities to identify the nature of
the incident and limit the damage. A site or network cannot be
considered to have good security if it does not respond to
incidents in a timely and effective fashion.
If a violator can be identified, appropriate action should be
taken to ensure that no further violations are caused. Exactly
what sanctions should be brought against a violator depend on
the nature of the incident and the site environment. For
example, a university may choose to bring internal disciplinary
action against a student violator.
Similarly, sites and networks should respond when notified of
security flaws in their systems. Sites and networks have the
responsibility to install fixes in their systems as they become
available.
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A Bibliography of Computer and Network Security Related Documents
United States Public Laws (PL) and Federal Policies
[1] P.L. 100-235, "The Computer Security Act of 1987", (Contained in
Appendix C of Citation No. 12, Vol II.), Jan. 8, 1988.
[2] P.L. 99-474 (H.R. 4718), "Computer Fraud and Abuse Act of 1986",
Oct. 16, 1986.
[3] P.L. 99-508 (H.R. 4952), "Electronic Communications Privacy Act
of 1986", Oct. 21, 1986.
[4] P.L. 99-591, "Paperwork Reduction Reauthorization Act of 1986",
Oct. 30, 1986.
[5] P.L. 93-579, "Privacy Act of 1984", Dec. 31, 1984.
[6] "National Security Decision Directive 145", (Contained in
Appendix C of Citation No. 12, Vol II.).
[7] "Security of Federal Automated Information Systems", (Contained
in Appendix C of Citation No. 12, Vol II.), Appendix III of,
Management of Federal Information Resources, Office of Management
and Budget (OMB), Circular A-130.
[8] "Protection of Government Contractor Telecommunications",
(Contained in Appendix C of Citation No. 12, Vol II.), National
Communications Security Instruction (NACSI) 6002.
Other Documents
[9] Secure Systems Study Committee, "Computers at Risk: Safe
Computing in the Information Age", Computer Science and
Technology Board, National Research Council, 2101 Constitution
Avenue, Washington, DC 20418, December 1990.
[10] Curry, D., "Improving the Security of Your UNIX System", Report
No. ITSTD-721-FR-90-21, SRI International, 333 Ravenswood Ave.,
Menlo Park, CA, 94025-3493, April 1990.
[11] Holbrook P., and J. Reynolds, Editors, "Site Security Handbook",
FYI 8, RFC 1244, CICNet, ISI, July 1991.
[12] "Industry Information Protection, Vols. I,II,III", Industry
Information Security Task Force, President's National
Telecommunications Advisory Committee, June 1988.
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[13] Jelen, G., "Information Security: An Elusive Goal", Report No.
P-85-8, Harvard University, Center for Information Policy
Research, 200 Akin, Cambridge, MA. 02138, June 1985.
[14] "Electronic Record Systems and Individual Privacy", OTA-CIT-296,
Congress of the United States, Office of Technology Assessment,
Washington, D.C. 20510, June 1986.
[15] "Defending Secrets, Sharing Data", OTA-CIT-310, Congress of the
United States, Office of Technology Assessment, Washington, D.C.
20510, October 1987.
[16] "Summary of General Legislation Relating to Privacy and Computer
Security", Appendix 1 of, COMPUTERS and PRIVACY: How the
Government Obtains, Verifies, Uses and Protects Personal Data,
GAO/IMTEC-90-70BR, United States General Accounting Office,
Washington, DC 20548, pp. 36-40, August 1990.
[17] Stout, E., "U.S. Geological Survey System Security Plan - FY
1990", U.S. Geological Survey ISD, MS809, Reston, VA, 22092, May
1990.
Security Considerations
If security considerations had not been so widely ignored in the
Internet, this memo would not have been possible.
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RFC 1281 Guidelines for the Secure Operation November 1991
Authors' Addresses
Richard D. Pethia
Software Engineering Institute
Carnegie Mellon University
Pittsburgh, Pennsylvania 15213-3890
Phone: (412) 268-7739
FAX: (412) 268-6989
EMail: rdp@cert.sei.cmu.edu
Stephen D. Crocker
Trusted Information Systems, Inc.
3060 Washington Road
Glenwood, Maryland 21738
Phone: (301) 854-6889
FAX: (301) 854-5363
EMail: crocker@tis.com
Barbara Y. Fraser
Software Engineering Institute
Carnegie Mellon University
Pittsburgh, Pennsylvania 15213-3890
Phone: (412) 268-5010
FAX: (412) 268-6989
EMail: byf@cert.sei.cmu.edu
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RFC, FYI, BCP