|Apache Struts 2 Documentation > Home > Security Bulletins > S2-004|
Directory traversal vulnerability while serving static content
|Who should read this||All Struts 2 developers|
|Impact of vulnerability||Read access to server filesystem resources (under certain application server environments)|
|Maximum security rating||Important|
|Recommendation||Developers should upgrade to Struts 2.0.12|
|Affected Software||Struts 2.0.0 - Struts 18.104.22.168|
|Original JIRA Ticket||WW-2779|
|Reporter||Csaba Barta and László Tóth, PricewaterhouseCoopers|
The Struts2 dispatcher logic by design allows to serve certain static resources found in the classpath of the web application for request URIs having a context relative path starting with "/struts/".
FilterDispatcher (in 2.0) and DefaultStaticContentLoader (in 2.1) have a security vulnerability that allows an attacker to traverse the directory structure and download files outside the "static" content folder, using double-encoded urls and relative paths, like:
Although not all container are vulnerable to this, the Struts2 dispatcher logic has to prevent access to static content outside the static resource folders.
As of Struts 2.0.12, the dispatcher logic was improved to correctly decode and normalize the request path before checking if static content serving applies for a given request.
You can obtain Struts 2.0.12 as a drop in replacement for Struts 22.214.171.124 to get the fixed Struts 2 core library.