Ultrix x.x /etc/rc.local security holes via /tmp/t1

Leonard Peirce peirce at gumby.cc.wmich.edu
Fri Mar 1 01:38:30 AEST 1991


In article <1991Feb28.131938.29631 at cs.widener.edu> brendan at cs.widener.edu (Brendan Kehoe) writes:
>In <1991Feb28.083356.6769 at watcgl.waterloo.edu>, idallen at watcgl.waterloo.edu writes:
>>On Ultrix (any version), if you happen to have directories named
>>/tmp/t1 or /tmp/t2, all kinds of nasty things will happen to your
>>/etc/motd and /etc/gettytab because /etc/rc.local assumes it can write
>>to these tmp names as files, and it edits the contents into your
>>/etc/motd and /etc/gettytab.
>
>  Suns have the same problem; just change the /tmp/t1 and /tmp/t2
>  names to /etc/t1 and /etc/t2 -- since rc.local's run as root, you'll
>  be fine.

You could just add

   rm -fr /tmp/t1 /tmp/t2

just before the edit to motd.

I always just comment out the entire mess.  I can maintain motd myself; I don't need
rc.local to change it for every reboot.

--
Leonard Peirce                  Internet:  peirce at gumby.cc.wmich.edu
Western Michigan University                peirce at gw.wmich.edu
Academic Computing Services     UUCP:      ...!uunet!sharkey!wmichgw!peirce
Kalamazoo, MI  49008            Phone:     (616) 387-5469



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