Software Engineering Institute

CWE-80: Improper Neutralization of Script-Related HTML Tags in a Web Page (Basic XSS) - CVE-2016-5061

Reportedly, the Aternity HTTPAgent, MacAgent, getExternalURL and retrieveTrustedUrl pages are susceptible to Cross-site scripting (XSS). An attacker may be able to craft a malicious script that can access any cookies, session tokens, or other sensitive information retained by the browser and used with the Aternity server.

CWE-829: Inclusion of Functionality from Untrusted Control Sphere - CVE-2016-5062

Reportedly, the Aternity server by default allows remote loading of Java MBeans using the getMBeansFromURL method without proper authentication due to a misconfiguration of JMX RMI services. A remote attacker may utilize this misconfiguration to register attacker-controlled MBeans, which are Java classes that can invoke Java language functionality including system commands, resulting in remote code execution with SYSTEM privileges.

Note that Aternity provides recommended firewall settings which would block exploit of this vulnerability; only misconfigured servers would be directly vulnerable.

The vulnerable configuration has been documented by Oracle for some time. As shown in the official documents:

“To disable both password authentication and SSL (namely to disable all security), you should set the following system properties when you start the Java VM.
com.sun.management.jmxremote.authenticate=false
com.sun.management.jmxremote.ssl=false
Caution - This configuration is insecure: any remote user who knows (or guesses) your port number and host name will be able to monitor and control your Java applications and platform. Furthermore, possible harm is not limited to the operations you define in your MBeans. A remote client could create a javax.management.loading.MLet MBean and use it to create new MBeans from arbitrary URLs, at least if there is no security manager. In other words, a rogue remote client could make your Java application execute arbitrary code.
Consequently, while disabling security might be acceptable for development, it is strongly recommended that you do not disable security for production systems.”

It is believed that Aternity version 9 and prior are affected by this vulnerability, but the CERT/CC has not received confirmation from the vendor.

A remote unauthenticated attacker may be able to craft a malicious script that can access any cookies, session tokens, or other sensitive information retained by the browser and used with the Aternity server, or execute code on the server with SYSTEM privileges.

The CERT/CC is currently unaware of a practical solution to this problem. However, the following workarounds are recommended:

Restrict port 14777

Restricting inbound remote access to Aternity via port 14777 mitigates this issue.