The Risks Digest

The RISKS Digest

Forum on Risks to the Public in Computers and Related Systems

ACM Committee on Computers and Public Policy, Peter G. Neumann, moderator

Volume 6 Issue 2

Monday, 4 January 1987


o Source Code is Counter to Viruses & Trojan Horses
Hal Guthery
o Viral VAXination?
Bryce Nesbitt
o Who is entitled to privacy?
Andy Freeman
o SSN / Passport / IRS ...
Joe Morris
Don Wegeng
Jean Marie Diaz
Martin Minow
Brint Cooper
John Pershing
o Info on RISKS (comp.risks)

Source Code is Counter to Viruses & Trojan Horses

"" <>
Mon, 4 Jan 88 07:51 EDT
As a little bit of reflection about the fact that almost all computers have
clocks in them will show, there is no protection in trying programs out with 
write-only harddisks or with privileges turned off.  Doing this only sets
the hook deeper.  In fact, anytime you run a program whose complete 
workings you do not and cannot understand you are at the mercy of the author
of the program and you are at risk.

One very good way to counter viruses and trojan horses is to insist on getting
the source code of any program you run.  This is summarized in the following 
pocketsize adage:


There are NO good reasons why software vendors shouldn't give you the source
code of any program they sell you.  The reason they don't currently is because
you could see what a mess the program really is.  In 999 cases out of 1,000
they don't know everything the program does and they certainly don't want you
looking over the code and telling them.

For a moment stop and think of all the execute only software you run on
your system.  Think of all the companies from whom you purchased this
software.  Think of all the pressure you put on them for bug fixes, new
features, and lower prices.  Think about the translation of these pressures
into pressures on programmers.  Suppose one of these programmers decides to
get just a little even ...  an occassional bad number, a lost record once a 
month, a couple pennies moved from here to there just for fun, a scrambled
directory entry once in a blue moon.  If the program does what it purports 
to do, where is the check?  The project leader?  The manager?  The president?
The venture capitalist?  You?  And who is responsible?  You!  And what can 
you do with a bunch of object code?  Turn off the harddisk?  Scan the program
for strings?  Deny privileges?  Piece of cake!

We are marginally able to answer the question "Does this piece of software
do what I want it to do?" but we are absolutely incapable of answering
the much more important question "Does this piece of software NOT do what 
I don't want it to do?"  Through this gaping hole in our capabilities enter 
viruses and trojan horses.  It is historically interesting that I can get a 
handle on the first question without the source code but I can get nowhere 
on the second without it.  As long as we willing to accept programs from 
software suppliers without the source code we, irresponsibly in my view, 
accept undue risk and invite disaster.

Viral VAXination? (Re: RISKS-6.1)

Bryce Nesbitt <bryce%hoser.Berkeley.EDU@ucbvax.Berkeley.EDU>
4 Jan 88 07:52:09 GMT
>      (Martin Minow THUNDR::MINOW ML3-5/U26 223-9922)  writes:
>Could a "harmless"  CHRISTMA-like virus attack a VAX/VMS system?   A
>recent network posting (RISKS?, LINKFAIL?) mentioned the possibility of a
>virus  hidden in SHAR files which are _executed_ as .COM  files to unpack

I'm surprised nobody has mentioned this:  Around here we don't "execute"
shar files to unpack them.  Instead there is a handly little utility called
"unshar".  I use a version on both Unix and my Amiga microcomputer.  It
internally handles all of the "legitimate" commands that a simple file packing
shar might contain (echo, wc, cat, if, test, #, exit, etc.).

It is much less vulnerable to attack.  To use the example of the poster, unshar
would simple report "unknow command" if a "SET PROC/PRIV=ALL" was quietly 
inserted in the middle of the file.

The comp.sources.unix and comp.sources.misc archives undoubtably have C
source code for the taking.

bryce@hoser.berkeley.EDU -or- ucbvax!hoser!bryce (or try "cogsci")

Who is entitled to privacy?

Andy Freeman <ANDY@Sushi.Stanford.EDU>
Thu 31 Dec 87 14:36:48-PST
[BTW - What happens if I send mail to]

The recent controversy over access to financial records of companies
(the companies want to control it and some find this offensive) is
somewhat similar to the continuing furor over records about people,
except that popular opinion in the latter case is that the people
should be able to control information about themselves.

Is there an essential difference here and what is it?  Is the corner
gas station entitled to more privacy than IBM?  Why?  Are all the
corner gas stations entitled to more privacy than IBM?  (The former
group is comparable in size to IBM.)

Note that in the current case, companies collected the information
about themselves while in most privacy invasion cases, the person
doesn't collect the information.  If one is going to argue on property
rights alone, these companies are entitled to control access while
people in the other case aren't.

SSN Required Disclosures

Joe Morris ( <>
Mon, 04 Jan 88 16:27:05 EST
In RISKS 6:1, David Albert reports that a post office clerk claims that the
disclosure of your SSN is no longer "optional" on the passport applications.
I can't say whether or not it is required, but the clerk is out of line in
any case.  The law on disclosure requirements is unusally direct:

  o The law prohibits any Federal, State, or local government entity
    (supposedly including related entities like State-suppported 
    universities) from denying any benefit or service because you
    didn't give your SSN, with certain specified exceptions.  These
    exceptions  are generally (a) where tax matters are involved; 
    (b) for a driver's license, and (c) in  certain cases where there
    was a pre-existing *legislative* requirement for the SSN.

  o Whenever a governmental organization requests the SSN, whether it is
    required or optional, you *must* be given what is called the "Privacy
    Act Notification".  This must tell you:

      (a) whether the request for the SSN is mandatory or optional;
      (b) what will happen if you don't give it;
      (c) under what authority it is being requested; and
      (d) what will be done with the information being requested.

    The Federal income tax forms you just received last week contain
    a good example of a well-constructed, complete Privacy Act Notification.
    (I knew that the IRS had to be good for something!)

  o There are no restrictions placed on the private sector governing the
    request for your SSN.

In other words, the passport application should have included a Privacy Act
notification, regardless of whether the SSN was optional or required.

After writing the above, I called the Department of State to see what they
had to offer.  According to the Passport Office, the SSN *is* required, as
of this morning (1/4/88); supposedly the Privacy Act Notification is on the
back of the application.  The DoS staffer I talked to insisted that
applications prior to today didn't require the SSN to be provided.

I assume that an application without the SSN would merely be returned; I
can't see them fining you for not completing the form.

Incidentally, does anyone in NetLand know of any case law covering the
SSN requests?  In particular, I'm interested in whether there have been
any cases involving state universities.  Although I wasn't involved, a  
friend was told by the legal office of his state university employer that
the law didn't apply to educational institutions, even if they were
funded by the state.  On the other hand, seeing how poorly the legislature
funded that university, maybe the lawyer had a point...
                                                            Joe Morris

Re: SSN Required Disclosures

Don Wegeng <Wegeng.Henr@Xerox.COM>
4 Jan 88 18:37:09 EST (Monday)
I saw a short article on this subject last week in one of the Rochester, NY
newspapers (I can probably find it at home if anyone wants a more specific
reference). As I recall, the article stated that the IRS is having problems
tracking down American citizens living abroad who don't file income tax
returns, so a law was passed which requires passport applicants to give
their SSN. The article didn't mention a fine, but stated that until new
application forms are available applicants who do not give their SSN will
probably be contacted for this information by the IRS.

It appears that the IRS and the INS are going to start sharing information,
undoubtably by connecting their computers in some way. The potential RISKS
in this have been discussed in this forum many times.

     [Also noted by Roy Maxion.  The following messages, for those of you who
     haven't already given up on RISKS-6.2, relate further to this topic.  This
     is a very popular subject, and it keeps flaring up spontaneously in RISKS.
     Thus I tend to be tolerant for a while, but then 

Re: mother's maiden name

Jean Marie Diaz <ambar@ATHENA.MIT.EDU>
Sun, 3 Jan 88 04:04:11 EST
Funny, I was opening a checking account today, and noticed that question
for the first time.  When I asked why they asked, I was told that it was
wanted "in case the bank wanted to verify who I was".  (In case of an
accident that cripples my writing hand?  Well, maybe...)

On a related note, someone can call BayBanks and make various inquiries
about my account, and even change the address to which my statements are
mailed, by knowing my account number and the amount & date of my last
deposit.  Sounds tricky enough?  Not for those of us who use Direct
Deposit to handle our paychecks...

      (Martin Minow THUNDR::MINOW ML3-5/U26 223-9922)
Date: 3 Jan 88 11:47
Subject: Mother's maiden name?

Why does American Express want to know your mother's maiden name?
When my pocket was picked two years ago, and my AmEx card, passport,
cash, and travellers checks stolen, AmEx (Paris) asked the obvious
questions plus my mother's maiden name.  As I understand it, it's
something you generally know, but the thief (who has your name, address,
phone number, SSnumber, and a lot of other information) probably doesn't
know.  AmEx (or whoever) is assuming the risk of giving a new card out
to an unknown person who might not have *any* identification at all,
and they evidently feel that this simple "password" is an authenticator
with a reasonable level of risk.

Incidently, AmEx lived up to its advertisements.  The U.S. embassy in Paris
managed to get me a replacement passport at 1 pm on a Saturday even though I
had absolutely no identification.  The embassy officer even lent me $10 so I
could take a photo and metro to my luggage (and money stash).  If I remember
correctly, they did ask for a mother's maiden name (or similar).

[Henry Mensch: American Express security ...]

Brint Cooper <abc@BRL.ARPA>
Sun, 3 Jan 88 13:12:06 EST
    [Coincidentally, Steve Anthony <Anthony@ALDERAAN.SCRC.Symbolics.COM>
    asked Why are Mother's Maiden Names Required?  PGN]

In registering patients for the first time, the Johns Hopkins Hospital
in Baltimore asks for Mother's maiden name as well.  This and other
information is factored into an algorithm for assigning a patient
identification number.  The hope is that by using such information, the
probability of two patients being assigned the same number is acceptably low.

Why not just assign numbers sequentially?  Inevitably, someone loses
their plate.  JHH wants to be able to retrieve their records by
reconstructing the number, if necessary.  Assigning a second number
would mean that the patient has two incomplete sets of medical records
in the hospital.  Some physicians would know the old number, others the
new.  Imagine what a malpractice lawyer would do with that!


Mon, 04 Jan 88 10:07 EST
When you're filling out the forms, it helps if you remember that the
MOTHER's MAIDEN NAME is essentially a password.  
          [and therefore subject to all of the problems of passwords...  PGN]
There is no particular reason why you have tell the truth, as long as you
remember what you DID say.

American Express security ...

John Pershing <>
4 Jan 88 08:49:17 EST
    From: Henry Mensch <>
    Does this mean that anyone who knows a bit about me can get my AmEx
    plate, too?

No, it merely means that anyone who knows a bit about you can get a new
AmEx card mailed to your house.  (Of course, there's nothing preventing
someone who knows your card number from sending AmEx a change of address
notification, and then requesting a new card!  However, this might raise
some eyebrows over at AmEx...)

Remember, too, that AmEx is liable for any fraud that is perpetrated in this
way.  They are taking a calculated risk — trying to make life as painless
as possible for their cardholders while maintaining a sensible amount of
security.  It has always seemed to me that AmEx strikes an extremely
reasonable balance in this respect.
                                     John A. Pershing Jr., IBM Yorktown Heights

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