HP released HP Operations Orchestration (HP OO) 10.51 in response to CVE-2016-1997. Note that by default, HP OO’s web interface does not require authentication, at all. However, it is very simple to enable so we assumed every rational admin that deploys it immediately goes into settings and turns on authentication. Unfortunately, this is not reality as seen via Shodan where the first page of results shows an Internet-addressable server with no authentication. As such, we consider this to be unauthenticated by default, but can be downgraded to authentication-required only by user configuration. Finally, since CVE-2016-1997 specifically calls out the use of Apache Commons Collections to gain execution, we do not use that library at all in exploitation.
HP OO has a sizeable REST API. Part of that API is described in
backwards-compatibility-servlet.xml. Here is an excerpt of the file:
<bean name="/wsExecutionBridgeService" class="org.springframework.remoting.httpinvoker.HttpInvokerServiceExporter">
<property name="service" ref="wsExecutionBridgeService"/>
<property name="serviceInterface" value="com.hp.oo.flow.execution.services.WSExecutionBridgeService"/>
The interesting part of this snippet is that
HttpInvokerServiceExport expects the payload of an HTTP POST request to be usable by an
ObjectInputStream. More importantly,
HttpInvokerServiceExport indirectly calls
readObject() on the payload which opens up the endpoint to deserialization vulnerabilities. For example, we can put a
DiskFileItem object in the HTTP payload and generate a stack trace. When authentication is disabled, anyone can reach
wsExecutionBridgeServer and trigger the above stack trace by POSTing objects to:
http://[target]:8080/oo/backwards-compatibility/wsExecutionBridgeService. However, it does require authentication if the administrator has enabled that feature as previously noted.
Tenable created a simple proof of concept called
consisting of a web page containing four buttons that, when pressed, exploit HP OO using four different ysoserial gadgets:
- FileUpload1: Creates a pseudo random named file in C:\Users\Public. Note that this file only lasts ~30 seconds before it gets deleted.
- BeanUtils1: Executes the command “cmd /c mkdir C:\Users\Public\beanutils_exploit”
- Spring1: Executes the command “cmd /c mkdir C:\Users\Public\spring1_exploit”
- Spring2: Executes the command “cmd /c mkdir C:\Users\Public\spring2_exploit”
Sorry, we just shared it with ZDI and not you.