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Apache Struts 2 framework REST plugin insecurely deserializes untrusted XML data

Vulnerability Note VU#112992

Original Release Date: 2017-09-06 | Last Revised: 2017-09-06

Overview

Apache Struts 2 framework, versions 2.5 to 2.5.12, with REST plugin insecurely deserializes untrusted XML data. A remote, unauthenticated attacker can leverage this vulnerability to execute arbitrary code in the context of the Struts application.

Description

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.

Impact

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.

Solution

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" />

Vendor Information

112992
Expand all

Apache Struts

Updated:  September 06, 2017

Status

  Affected

Vendor Statement

No statement is currently available from the vendor regarding this vulnerability.

Vendor Information

We are not aware of further vendor information regarding this vulnerability.

Vendor References

https://struts.apache.org/docs/s2-052.html

Addendum

There are no additional comments at this time.

If you have feedback, comments, or additional information about this vulnerability, please send us email.


CVSS Metrics

Group Score Vector
Base 10.0 AV:N/AC:L/Au:N/C:C/I:C/A:C
Temporal 8.3 E:F/RL:OF/RC:C
Environmental 8.3 CDP:ND/TD:H/CR:ND/IR:ND/AR:ND

References

Credit

Man Yue Mo of lgtm is credited with reporting this vulnerability to the vendor.

This document was written by Joel Land.

Other Information

CVE IDs: CVE-2017-9805
Date Public: 2017-09-05
Date First Published: 2017-09-06
Date Last Updated: 2017-09-06 13:16 UTC
Document Revision: 13

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