Software Engineering Institute

CWE-502: Deserialization of Untrusted Data - CVE-2017-9805

In Apache Struts 2 framework, versions 2.5 to 2.5.12, the REST plugin uses XStreamHandler with an instance of XStream to deserialize XML data. Because there is no type filtering, a remote, unauthenticated attacker may send a specially crafted XML payload to execute arbitrary code in the context of the Struts application.

Refer to the researcher's blog post for more information about this vulnerability. A Metasploit module with exploit code is publicly available.

A remote, unauthenticated attacker may send a specially crafted XML payload to execute arbitrary code on vulnerable servers in the context of the Struts application.

Apply an update

The vendor has released version 2.5.13 to address this vulnerability. No workaround is possible according to the vendor, so patching is strongly recommended.

Remove or limit the REST plugin

If it is not used, consider removing the REST plugin. Per the vendor, it is also possible to limit its functionality to normal server pages or JSON with the following configuration change in struts.xml:

<constant name="struts.action.extension" value="xhtml,,json" />