apache Struts 업데이트 안내 (S2-052)

Possible Remote Code Execution attack when using the Struts REST plugin with XStream handler to handle XML payloads
Who should read this

All Struts 2 developers and users

Impact of vulnerability

A RCE attack is possible when using the Struts REST plugin with XStream handler to deserialise XML requests

Maximum security rating

Critical

Recommendation

Upgrade to Struts 2.5.13

Affected Software

Struts 2.5 - Struts 2.5.12

Reporter

Man Yue Mo <mmo at semmle dot com> (lgtm.com / Semmle). More information on the lgtm.com blog: https://lgtm.com/blog

CVE Identifier

CVE-2017-9805

Problem
The REST Plugin is using a XStreamHandler with an instance of XStream for deserialization without any type filtering and this can lead to Remote Code Execution when deserializing XML payloads.

Solution

Upgrade to Apache Struts version 2.5.13.

Backward compatibility
It is possible that some REST actions stop working because of applied default restrictions on available classes. In such case please investigate the new interfaces that was introduced to allow define class restrictions per action, those interfaces are:

org.apache.struts2.rest.handler.AllowedClasses
org.apache.struts2.rest.handler.AllowedClassNames
org.apache.struts2.rest.handler.XStreamPermissionProvider
Workaround
No workaround is possible, the best option is to remove the Struts REST plugin when not used or limit it to server normal pages and JSONs only:

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