From: Samuel Tardieu <sam@inf.enst.fr>
Date: Fri, 12 Apr 1996 04:08:00 +0800
To: me@muddcs.cs.hmc.edu (Michael Elkins)
Subject: Re: Scientologists may subpoena anonymous remailer records
In-Reply-To: <199604110647.XAA05823@muddcs.cs.hmc.edu>
Message-ID: <qw6wx3mhnja.fsf@gargantua.enst.fr>
MIME-Version: 1.0
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>>>>> "Michael" == Michael Elkins <me@muddcs.cs.hmc.edu> writes:

Michael> I've heard several people make this statement...  Can anyone
Michael> confirm that it is really possible to log the uid (username)
Michael> of the person making the http request?  I know they can get
Michael> your ip address, but I'm skeptical of getting the username.

There is no general rule, it depends on your system, your system
administrator, your browser, .... If you use Unix, there is no way to
know who is at the other end of a socket without using either:
 
  1) finger- or rusers-like information, which is only a guess than
     may easily be defeated;

  2) a "identity daemon", which is run on port 113 and may be queried
     by a host to which a connection is being made.

This kind of identity daemon sometimes has an option which makes it
look for a file in the user's home directory before answering ; if
this file is present, then the user-id won't be disclosed. It is also
very time-consuming for a WWW server to make such a TCP connection
each time a request is made, it slows down the request a lot.

Anyway, the use of a proxy may help you in that the user-id will
probably "nobody". You stay anonymous, unless your proxy's manager
keeps the logs.

The other way to get your identity is... getting cooperation from
yourself ! There was a bug in Netscape 2.0 which made it possible to
make you send a mail without even realizing it when browsing some
pages (using a form with a mailto: action and a piece of JavaScript to
submit the form). Other browsers may well send your user-id and/or you
real name across the network in a browser-defined header. This must be
checked on a browser per browser basis, since each browser is free to
add any header it wants.

  Sam
- -- 
"La cervelle des petits enfants, ca doit avoir comme un petit gout de noisette"
                                                       Charles Baudelaire

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