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Re: man problem


From: zen () TROUBLE ORG (d)
Date: Wed, 24 Dec 1997 15:34:46 -0800


I just noticed a problem with the man system (version 2.3.10) on my Linux
box: /usr/man contains the .gz'd man pages:
[...]
When I execute man, a temporary file containing the un-zipped manpage is
created in /tmp. The name of the tmp-file usually is "zman<PID>aaa",
e.g. "zman10849aaa". This can be exploited with a simple symlink attack:

Pretty much the same with unformatted 'roff pages on unix (at least with
my suns around here; I assume others mostly do the same), with variously
different filenames; sunos uses /tmp/man{pid}, solaris /tmp/mpa+cruft, etc.
Another reason to use catman, I guess.

What a neat little trick.  I never thought man would be a security hole.

-- d



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