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- CA-92:19 CERT Advisory
- December 7, 1992
- Keystroke Logging Banner
-
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-
- The CERT Coordination Center has received information from the United States
- Department of Justice, General Litigation and Legal Advice Section, Criminal
- Division, regarding keystroke monitoring by computer systems administrators,
- as a method of protecting computer systems from unauthorized access.
-
- The information that follows is based on the Justice Department's advice
- to all federal agencies. CERT strongly suggests adding a notice banner
- such as the one included below to all systems. Sites not covered by U.S.
- law should consult their legal counsel.
-
- -----------------------------------------------------------------------------
-
- The legality of such monitoring is governed by 18 U.S.C. section 2510
- et seq. That statute was last amended in 1986, years before the words
- "virus" and "worm" became part of our everyday vocabulary. Therefore,
- not surprisingly, the statute does not directly address the propriety
- of keystroke monitoring by system administrators.
-
- Attorneys for the Department have engaged in a review of the statute
- and its legislative history. We believe that such keystroke monitoring
- of intruders may be defensible under the statute. However, the statute
- does not expressly authorize such monitoring. Moreover, no court has
- yet had an opportunity to rule on this issue. If the courts were to
- decide that such monitoring is improper, it would potentially give rise
- to both criminal and civil liability for system administrators.
- Therefore, absent clear guidance from the courts, we believe it is
- advisable for system administrators who will be engaged in such
- monitoring to give notice to those who would be subject to monitoring
- that, by using the system, they are expressly consenting to such
- monitoring. Since it is important that unauthorized intruders be given
- notice, some form of banner notice at the time of signing on to the
- system is required. Simply providing written notice in advance to only
- authorized users will not be sufficient to place outside hackers on
- notice.
-
- An agency's banner should give clear and unequivocal notice to
- intruders that by signing onto the system they are expressly consenting
- to such monitoring. The banner should also indicate to authorized
- users that they may be monitored during the effort to monitor the
- intruder (e.g., if a hacker is downloading a user's file, keystroke
- monitoring will intercept both the hacker's download command and the
- authorized user's file). We also understand that system administrators
- may in some cases monitor authorized users in the course of routine
- system maintenance. If this is the case, the banner should indicate
- this fact. An example of an appropriate banner might be as follows:
-
-
-
- This system is for the use of authorized users only.
- Individuals using this computer system without authority, or in
- excess of their authority, are subject to having all of their
- activities on this system monitored and recorded by system
- personnel.
-
- In the course of monitoring individuals improperly using this
- system, or in the course of system maintenance, the activities
- of authorized users may also be monitored.
-
- Anyone using this system expressly consents to such monitoring
- and is advised that if such monitoring reveals possible
- evidence of criminal activity, system personnel may provide the
- evidence of such monitoring to law enforcement officials.
-
-
-
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- Each site using this suggested banner should tailor it to their precise
- needs. Any questions should be directed to your organization's legal
- counsel.
-
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- The CERT Coordination Center wishes to thank Robert S. Mueller, III,
- Scott Charney and Marty Stansell-Gamm from the United States Department
- of Justice for their help in preparing this Advisory.
-
- -----------------------------------------------------------------------------
- If you believe that your system has been compromised, contact the CERT
- Coordination Center or your representative in FIRST (Forum of Incident
- Response and Security Teams).
-
- Internet E-mail: cert@cert.org
- Telephone: 412-268-7090 (24-hour hotline)
- CERT personnel answer 7:30 a.m.-6:00 p.m. EST(GMT-5)/EDT(GMT-4),
- on call for emergencies during other hours.
-
- CERT Coordination Center
- Software Engineering Institute
- Carnegie Mellon University
- Pittsburgh, PA 15213-3890
-
- Past advisories, information about FIRST representatives, and other
- information related to computer security are available for anonymous FTP
- from cert.org (192.88.209.5).
-
-