Security hole in smail 2.3's handling of ~/.forward

[levy at ttrdc.UUCP]

In article <3150 at osu-eddie.UUCP>, karl at osu-eddie.UUCP writes:
>The posting of smail 2.3 has a large security hole in mail delivery
>with regard to the use of ~/.forward files. 
>
>[code]
>
>This is not sufficiently careful.  It has not checked for things like
>.forward being writable a non-owner of the file, a transparent
>security hole.  I also recommend that checks be done on the home
>directory to see that it, too, is writable only by the owner, lest
>some cracker "give" you a .forward file, and suddenly you stop getting
>mail without knowing why.
>-- 
>Karl

And not only check the home directory, but the one above it, and the one
above that, etc....  (gee you can have such fun if some careless sysadmin
leaves / world writeable).
-- 
 -------------------------------    Disclaimer:  The views contained herein are
|            dan levy            |  my own and are not at all those of my em-
|         an engihacker @        |  ployer or the administrator of any computer
| at&t computer systems division |  upon which I may hack.
|        skokie, illinois        |
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