Date:         Thu, 16 Nov 2000 13:05:30 -0500
From: John Madden <weez@AVENIR.DHS.ORG>
Subject:      Re: Joe's Own Editor File Link Vulnerability
To: BUGTRAQ@SECURITYFOCUS.COM

> VULNERABILITY EXAMPLE
> - - Root is logged in remote
> - - Malicious user (X) notices that root is editing file.txt in /tmp
>   (where X has write permissions)
> - - X creates a link from /etc/passwd (root = write permission) to
>   /tmp/DEADJOE
> - - Root's connection is dropped or terminated under abnormal conditions
>   (for example: root halts the system) before file.txt is saved, the
>   editor will write a rescue copy to /tmp/DEADJOE

Correction: joe creates DEADJOE in the present working directory, not
/tmp.  root would have to be working in /tmp for this to work.  Of course,
the link could be in /home/foouser to /etc/passwd, but that makes the
exploit a bit more difficult.

(Tested on slackware 7.0, default joe installation)

John





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