Handbook of Infosec Terms 2.0/Handbook_of_Infosec_Terms_Version_2.0_ISSO.iso/text/secpubs/hansen.txt

Text File | 1995-09-15 | 15KB | 253 lines

                Legal Issues, A Site Manager's Nightmare

                            Stephen E. Hansen

                           Stanford University





               Excerpts from the Electronic Communications
                           Privacy Act of 1986


           2511(2)(a)(i) It shall not be unlawful under this chapter for
           an operator of a switchboard, or an officer, employee, or
           agent of a provider of wire or electronic communication
           service, whose facilities are used in the transmission of a
           wire communication, to intercept, disclose, or use that
           communication in the normal course of his employment while
           engaged in any activity which is a necessary incident to the
           rendition of his service or to the protection of the rights or
           property of the provider of that service, except that a
           provider of wire communication service to the public shall not
           utilize service observing or random monitoring except for
           mechanical or service quality control checks.

           2511(2)(h)(ii) It shall not be unlawful under this chapter
           record the fact that a wire or electronic communication was
           initiated or completed in order to protect such provider,
           another provider furnishing service toward the completion of
           the wire or electronic communication, or a user of that
           service, from fraudulent, unlawful or abusive use of such
           service.


1. Logging For Fun and Profit

           What do we mean when we talk about computer security? For most
of us it means the protection against the loss of or tampering with
computer based information and protection against possible denial of
service. If you are a site manager, your users, clients, or employers
want assurances that their files won't be read if they don't want them
to be, won't be modified or deleted without their consent, and want to
be able to access their files when necessary. So we take steps to provide
and enforce various security mechanisms that are aimed at protecting the
privacy of information and access to resources. But there are often
tradeoffs between privacy and security that must be recognized and
evaluated. On many systems every time you login, logout, send a mail
message, print a file, or copy data to or from another system the who,
what, where, and when of the transaction is logged (on some systems every
command is logged). Not too long ago there was a rather spirited
discussion on one of our local network bulletin boards on whether or not
this logging was an invasion of privacy. If this seems silly to you,
consider your reaction if you learned that the US Post Office was keeping
logs of the source and destination of every piece of mail that you sent.
On the other hand, the phone companies have been doing this very thing
with your phone calls for years and years for billing purposes. But the
fact that many systems log this information in pursuit of several
admirable goals such as ensuring reliability and security is not always
appreciated by the average user.

           From a legal perspective this type of service-related logging
is allowed under section 2511(2)(h)(ii) of the Electronic Communications
Privacy Act of 1986,

           "It shall not be unlawful under this chapter... for a provider of
           electronic communication service to record the fact that a wire
           or electronic communication was initiated or completed in order
           to protect such provider, another provider furnishing service
           toward the completion of the wire or electronic communication, or
           a user of that service, from fraudulent, unlawful or abusive use
           of such service."

But for the security conscious (fanatic, paranoid?) administrator the
tendency is to log more and more information about more and more
activities. It used to be that resource limits (i.e. limited disk space
and low density tape) provided a natural governor on these activities,
but for many systems these limits no longer applies. At what point does
logging for the purpose of verification, fault tracing, or resource
billing become service observing or random monitoring, which is
prohibited under section 2511(2)(a)(i) of the Act. So here we have a
federal law that provides the means to charge and prosecute people who
access private data on our systems, but if we are not careful we may find
ourselves in violation of the law by acting too aggressively on our own
for the purpose of maintaining security.

2. Investigator or Accomplice

           When a security breach is detected or suspected it may be
necessary to override normal file protection controls and scan files
belonging to system users. In most cases ethics, and in some cases the
law, tells you to get permission from the users before looking at their
files. This may not be practical, however, due to time constraints or due
to the possibility of alerting a suspect

           The first time I had to deal with a break-in the only legal
issue we considered was did, "we have enough evidence." Our main concern
was getting the law enforcement groups interested in our problem. The
"bad guys" were almost certainly from outside our organization. We
quickly restricted access to one account on one system, and the
legitimate user of that account agreed to use a different one while the
investigation was in progress. We set things up so that every time the
compromised account was accessed, the bit-streams in both directions were
logged, both the keystrokes coming in and what was going out to their
screens. This information turned out to be invaluable in quickly
notifying managers all over the country that their systems had been
penetrated. It gave us names, times, and places of the machines that had
been accessed by these "Crackers". It was key to tracking down the source
of these break-ins.

           It was only later that someone else made the comment, "What if
these guys used your system to break into someone else's system: could
the owners of these other systems come after you for giving the Crackers
the means to do it?". Now this was a rather chilling thought. I have for
some time advocated the idea that if it is possible to control and
monitor a break-in, then you should do so in order to collect information
and track down and arrest those responsible. There are, of course, real
risks to your own system in this, but if you can stay on top of things
those risks can be minimized. However, if there are need to get them out
in the open and address them. Cliff Stoll's pursuit of the West German
hackers is only the most well known of probably dozens of successful uses
of this strategy. If we are open to civil or criminal liability by
permitting the attackers to use our systems while we chase them down then
we will have lost one of our most potent offensive weapons. We will be
reduced to the unsatisfactory alternative of merely shutting them out and
funding the alarm, with the knowledge that not everyone will hear it or
heed it. It is likely that additional legislation is needed here. I have
heard some prosecutors say that new laws relating to computer crimes are
not necessary, that existing law on trespass, theft, trade secrets, etc.
are sufficient, but I am doubtful. The art of applying existing law to
computer-related activities is still an uncertain one. I am uncomfortable
with the idea that someone may make the analogy between our logging and
tracking operation and someone allowing a thief to use his garage as a
storage place for stolen goods while he tries to follow the bad guy
around to see where he lives. Sure the police can do it but they would
frown on you doing it on your own. I think the analogy is a bad one, I
don't think it 'maps' very well. But would an MIS VP who's had his system
trashed agree? Would Bell South agree? Would a judge or jury agree? I
think it's took a close look at this one.

3. Vigilant Watchman or Peeping Tom

           The next security problem I dealt with was not a break-in from
the outside, but rather it was a legitimate user, a graduate student who
wasn't happy with how quickly we responded to problems. ("Steve! The
print spooler's stuck again!"). This guy got root access somehow (via a
trojan Is command in /tmp directory I think) and booby-trapped a module
that is linked into most system utilities. He added a small code fragment
to this module that looked for the presence of a uniquely named copy of
the csh shell in /tmp. If it found it would change its ownership to root
and turn on its setuid bit, giving him root access. What got us on to him
was finding a setuid root file buried in his directories during a
security scan. We went and looked at that file and found that it was a
setuid root copy of csh. We went looking around and found a directory
containing plain text and encrypted files. The plain text files appeared
to be the source for some of the encrypted files that he'd neglected to
remove. The contents of some of the plain were sufficiently worrisome
that we spent the time to break the encryption and read the rest of the
files.  It was all rather incriminating.

    At this point we went to the student's advisor who was also the owner of the
system and showed him what we'd found. The professor called in the student,
showed him the evidence and chew him out.  He was told that if he wanted to
graduate he'd better behave. He did, got his PhD, left us on good terms, and is
now on the staff of the research arm of a major telecommunications company. In
this case, once we found the file that provided super user access to the system
we felt justified in looking further.  Today, we would operate a bit differently,
if we found a setuid root file in a user's directory we would immediately close
and archive the account and get approval from the user, or, if necessary, the
system's owner before looking further. There a at least a couple of reasons for
this. One is a greater sensitivity toward the privacy of user files. The other
is legal, the Privacy Act in section 2701 provides penalties for anyone who
"obtains, alters, or prevents authorized access to a... electronic communication
while it is in electronic storage...". But while it appears to give us an out by
making an exception "... with respect to conduct authorized by the person or
entity providing a ... electronic communication service" the Act has only been
tested with respect to telephone monitoring. To me, the key words here are
"conduct authorized".  What constitutes authorized conduct?

     But let's take it a step further, what if you find out that someone has
compromised yo just one or more user accounts, but all the way to root, to the
super user. Do you scan everyone's files? Don't you have to? Let's make it real
sticky and say that you found that the slimemold who in has been hiding account
and password information in old mail files of what seems to b Do you go looking
in everybody's mail, including your boss's, the Provost's, the Director of the
Human Resources Department, Major Filbert's? Again, don't you have to? What a
mess! Our ma in, and the one least satisfying in its resolution, had a number of
system administrators on looking at a lot of private, and in some cases very
personal, mail, just to find a few caches of important system information hidden
by one or more outside intruders. This is a very distasteful thing the people
involved enjoyed it, and the anger directed at the vandals who made this
necessary was considerable. But even though most of the users soon found out
about the break-ins and knew we were prying intruders out of the file system I
done don't think they realized just how invasive our h own private files,
otherwise we may very well had a number of very outraged users on our r

     The best solution to this problem would be to state in advance of issuing any
account system administrators reserve the right to review a user's files in
certain situations, our duct". One of these situations is when a reasonable
suspicion exists that the files cont activities that are either illegal or
violate the system's or organization's rules of conduct. should be in writing and
signed off by each user. It should state what you will and will no conditions,
and why. Especially why. This preemptive tactic of laying out the rules in
advance implemented by every site. A side benefit of implementing these
guidelines is that it w administrators to think about, in advance, the way in
which they will or can respond to s type. In the heat of the moment it is all too
easy to rush in and do something you'll regret later.  Your staff will have pre-
established procedures to follow, even if you're not immediately available to
advise them. By setting up your procedures in advance you can get management to
pre-approve your responses, something that you probably won't want to take the
time for when the day comes. And if push and you have to go in and justify your
actions you will want to be able to show that you were following well known
procedures designed to protect the privacy and security of all users.

     Having an agreed-to set of rights and rules for both users and system
administrators clarifies your relationship. In many or most non-educational or
commercial service sites such rights and rules are likely to be rather-one sided
towards the administrators, but at least you know where you stand by writing
these agreements in advance. Running such an agreement and your procedures by the
legal department may be useful in showing you a few hard patches of ground in the
swamp of computer law.


4.  Conclusions

    Our logging of the various system activities are, in general, necessary for
the smooth operation of the systems, but it can be taken to extremes. You risk
drowning in information and possibly violating privacy laws or regulations.


    Allowing intruders to remain on your system and use it as a base of operations
while you collect evidence and attempt to track them down may have some legal
liability if they subsequently break into another system. The potential for
liability urgently needs evaluation by legal professionals.

    Your legal right to search a user's files without permission or prior
agreement is uncertain. An agreed to set of rights, rules, and procedures between
users and administration can be helpful in determining the legality of your
actions in the event of unauthorized access. The existence of guidelines and
procedures can be invaluable in responding quickly, legally, and ethically to
real or suspected security problems.

    I've focused on the Federal Electronic Communications Privacy Act of 1986.
This is certainly not the only law that will apply in the case of unauthorized
access but it does cover a number of likely situations, and unlike the Computer
Fraud and Abuse Act of 1986 it is not restricted to government systems. In
addition, several states have very similar statues and more are likely to follow.