CERT Advisory 052

eZine lover (@eZine)

Published in 

CERT Advisory

 · 4 years ago

  

 
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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. 

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    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. 

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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). 

 
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