Apache Struts2 S2-056(CVE-2018-1327)

Summary

A crafted XML request can be used to perform a DoS attack when using the Struts REST plugin

Problem

The REST Plugin is using XStream library which is vulnerable and allow perform a DoS attack when using a malicious request with specially crafted XML payload.

Solution

Upgrade to the Apache Struts version 2.5.16 and switch to an optional Jackson XML handler as described here. Another option is to implement a custom XML handler based on the Jackson XML handler from the Apache Struts 2.5.16.

Backward compatibility

No backward incompatibility issues are expected.

Workaround

Use Jackson XML handler instead of the default XStream handler as described here.