Once an user is authenticated on Jolokia, he can potentially trigger arbitrary code execution.
In details, in ActiveMQ configurations, jetty allows org.jolokia.http.AgentServlet to handler request to /api/jolokia
org.jolokia.http.HttpRequestHandler#handlePostRequest is able to create JmxRequest through JSONObject. And calls to org.jolokia.http.HttpRequestHandler#executeRequest.
Into deeper calling stacks, org.jolokia.handler.ExecHandler#doHandleRequest is able to invoke through refection.
And then, RCE is able to be achieved via jdk.management.jfr.FlightRecorderMXBeanImpl which exists on Java version above 11.
1 Call newRecording.
2 Call setConfiguration. And a webshell data hides in it.
3 Call startRecording.
4 Call copyTo method. The webshell will be written to a .jsp file.
The mitigation is to restrict (by default) the actions authorized on Jolokia, or disable Jolokia. A more restrictive Jolokia configuration has been defined in default ActiveMQ distribution. We encourage users to upgrade to ActiveMQ distributions version including updated Jolokia configuration: 5.16.6, 5.17.4, 5.18.0, 6.0.0.