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Date: Mon, 28 Feb 2011 14:40:36 -0500
From: Dan Rosenberg <dan.j.rosenberg@...il.com>
To: oss-security@...ts.openwall.com
Cc: Helgi Þormar Þorbjörnsson <helgi@....net>
Subject: Re: CVE Request: PEAR Installer 1.9.1 <= - Symlink Attack

I'm not familiar with this code or any of the context surrounding this
fix, but it appears to be an incomplete fix.  Checking for existence
of a symlink and then opening the resource leaves open a window during
which a legitimate file can be replaced with a symlink.  Also, I don't
see a reason why a hard link couldn't be used for exploitation
instead.

-Dan

2011/2/28 Helgi Þormar Þorbjörnsson <helgi@....net>:
> The lack of symlink checks in the PEAR installer 1.9.1 <= while doing
> installation and upgrades, which initiate various system write
> operations, can cause privileged users unknowingly to overwrite
> critical system files.
>
> Further information can be found in this temporary advisory
> http://pear.php.net/advisory-20110228.txt and the
>
> Fixes can be found at http://news.php.net/php.pear.cvs/61264
>
> - Helgi
>

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