oss-sec mailing list archives
Re: CVE Request: PEAR Installer 1.9.1 <= - Symlink Attack
From: Pierre Joye <pierre.php () gmail com>
Date: Tue, 1 Mar 2011 10:11:19 +0100
hi, 2011/2/28 Dan Rosenberg <dan.j.rosenberg () gmail com>:
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.
Not sure it is fixable, or maybe using a lock on the symbolic link while fetching its target (to be tested to be sure that such locks cannot be overridden from shell).
Also, I don't see a reason why a hard link couldn't be used for exploitation instead.
Hard link are not detectable (lstat), they are treated like normal files. Cheers, -- Pierre @pierrejoye | http://blog.thepimp.net | http://www.libgd.org
Current thread:
- CVE Request: PEAR Installer 1.9.1 <= - Symlink Attack Helgi Þormar Þorbjörnsson (Feb 28)
- Re: CVE Request: PEAR Installer 1.9.1 <= - Symlink Attack Dan Rosenberg (Feb 28)
- Re: CVE Request: PEAR Installer 1.9.1 <= - Symlink Attack Pierre Joye (Mar 01)
- Re: CVE Request: PEAR Installer 1.9.1 <= - Symlink Attack Helgi Þormar Þorbjörnsson (Mar 01)
- Re: CVE Request: PEAR Installer 1.9.1 <= - Symlink Attack Vincent Danen (Mar 03)
- Re: CVE Request: PEAR Installer 1.9.1 <= - Symlink Attack Dan Rosenberg (Mar 01)
- Re: CVE Request: PEAR Installer 1.9.1 <= - Symlink Attack Pierre Joye (Mar 01)
- Re: CVE Request: PEAR Installer 1.9.1 <= - Symlink Attack Helgi Þormar Þorbjörnsson (Mar 01)
- Re: CVE Request: PEAR Installer 1.9.1 <= - Symlink Attack Helgi Þormar Þorbjörnsson (Mar 08)
- Re: CVE Request: PEAR Installer 1.9.1 <= - Symlink Attack Vincent Danen (Mar 11)
- Re: CVE Request: PEAR Installer 1.9.1 <= - Symlink Attack Pierre Joye (Mar 01)
- Re: CVE Request: PEAR Installer 1.9.1 <= - Symlink Attack Dan Rosenberg (Feb 28)