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Re: smbd remote file creation vulnerability
From: Simple Nomad <thegnome () nmrc org>
Date: Tue, 26 Jun 2001 16:46:01 -0400 (EDT)

The limit on the netbios name length must include the ../../../ as a part
of the name, so you've blown 9 characters right there to get to the root
dir. Otherwise you could get to /etc/crontab or something and the exploit
would not require a symlink. So the file can be created remotely, but as
for the symlink that requires local access.

Of course you could try to point /tmp/x.log to ~personaldir/tmp/x.log
which points to /etc/passwd, but that still won't work under the Openwall
patch (just checked to make sure).

-         Simple Nomad          -     "No rest for the Wicca'd"     -
-      thegnome () nmrc org        -                                   -
-  thegnome () razor bindview com  - www.nmrc.org   razor.bindview.com -

On Tue, 26 Jun 2001, Pavol Luptak wrote:

On Tue, Jun 26, 2001 at 09:53:29AM +0300, Jarno Huuskonen wrote:
On Mon, Jun 25, Pavol Luptak wrote:
Linux kernels with openwall patch (with restricted links in /tmp) are
imunne to this type of attack (following symlinks does not work, link
owner does not match with file's owner).

The symlink restrictions work only in /tmp (mode 1777) directories, so
making the symlink in your own homedir still works (should work).

Yes, the symlink does not have to be in /tmp, but you have to ensure
the path to your symlink in your own homedir is enough short to fill in
NetBIOS name (about 15 characters).
[wilder () hq alert sk] [http://hq.alert.sk/~wilder] [talker: ttt.sk 5678]

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