14 Sep

WordPress Plugin Security Review: Regenerate Thumbnails

For our nineteenth security review of a WordPress plugin based on the voting of our customers, we reviewed the plugin Regenerate Thumbnails.

If you are not yet a customer of the service you can currently sign up for the service for half off and then start suggesting and voting on plugins to get security reviews. For those already using the service that haven’t already suggested and voted for plugins to receive a review, you can start doing that here. You can use our tool for doing limited automated security checks of plugins  (now accessible through a WordPress plugin of its own) to see if plugins you are using have possible issues that would make them good candidates to get a review. You can also order a review of a plugin separately from our service.

The review was done on version 3.0.2 of Regenerate Thumbnails. We checked for the following issues during this review:

  • Insecure file upload handling (this is the cause of the most exploited type of vulnerability, arbitrary file upload)
  • Deserialization of untrusted data
  • Security issues with functions accessible through WordPress’ AJAX functionality (those are a common source of disclosed vulnerabilities these days)
  • Persistent cross-site scripting (XSS) vulnerabilities in publicly accessible portions of the plugin
  • Cross-site request forgery (CSRF) vulnerabilities in the admin portion of the plugin
  • SQL injection vulnerabilities (the code that handles requests to the database)
  • Reflected cross-site scripting (XSS) vulnerabilities
  • Security issues with functions accessible through any of the plugin’s shortcodes
  • Security issues with functions accessible through the admin_action action
  • Security issues with functions accessible through the admin_init action
  • Security issues with import/export functionality
  • Security issues with usage of is_admin()
  • Host header injection vulnerabilities
  • Lack of protection against unintended direct access of PHP files
  • Insecure and unwarranted requests to third-party websites
  • Any additional possible issues identified by our Plugin Security Checker

Results

We found one really minor issue.

Lack of Protection Against Direct Access to PHP Files

Two .php file in the plugin are not intended to be directly accessed but do not contain protection against direct access. The files only define classes, so there is nothing exploitable if they are accessed and adding a restriction has limited value.

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