On August 2nd, 2011 Mark posted detailed blog mentioning technical details and scripts of WordPress hack plugin called “TimThumb”. TimThumb plugin is a simple, flexible, PHP script that resizes images for your blogs. It is a small PHP script for cropping, zooming and resizing web images like jpg, png, gif etc. As discovered my Mark, TimThumb plugin has a File upload vulnerability. An attacker can upload any file on the server to execute it.
This plugin is used by many people on their WordPress blogs and also it is bundled with many other different WordPress themes and plugin. If you have vulnerable version of this plugin, you should change the code to fix the issue as per workaround provided by Mark. File uploading vulnerabilities are not new but they are constantly used to compromise or hack the websites. There are already thousands of WordPress themes and plugin available over the Internet and new ones are coming every day. You should not blindly install each and every plugin. Do some homework before using any theme or plugin.
Security is really important for your websites. You take a lot of efforts to write on your websites and one vulnerabilityin any theme or plugin can provide massive damage to your website and your business. The above one is great example of this. Mark’s website got hacked due to this vulnerability and attacker injected some advertising code into his webpage’s. Attacker could have done more damage to his website since he/she can have the access to his server. You should immediately check your themes and plugin for any vulnerability.
To find, if your theme or plugin has vulnerability or not is to use Google search engine. Use theme name or plugin name along with name “vulnerability” in search string. For example, to search for TimThumb bug, search “TimThumb vulnerability” in the Google.