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How to prevent Java RMI class loader exploit with AdminServer

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TitleHow to prevent Java RMI class loader exploit with AdminServer
URL NameHow-to-prevent-Java-RMI-class-loader-exploit-with-AdminServer
Article Number000176908
EnvironmentProduct: OpenEdge
Version: 10.2x, 11.x to 11.6 inclusive
OS: All Operating Systems
Other: Java RMI, AdminServer
Question/Problem Description
How to prevent malicious java code execution when using RMI?
How to prevent anonymous requests to load and execute Java classes from a remote URL when using RMI?
Java version shipped with OpenEdge allows unauthenticated remote attackers to specify arbitrary URLs from which to load and execute malicious Java classes via port 20931.
Steps to Reproduce
Clarifying Information
Java Remote Method Invocation (RMI) services permit remote anonymous users to load arbitrary Java classes via the Class Loader.
Java classes could contain system commands: pwd, whoami, to recover stored password hashes and in-memory cleartext credentials.
RMI services handle anonymous requests to load and execute Java classes from any remote (HTTP) URL by default.
RMI services are typically run under a highly privileged user context.
Error Message
Defect Number
Enhancement Number
The Java RMI class loader exploit is resolved in Java 7.21, where the RMI property java.rmi.server.useCodebaseOnly defaults to true by default.

This change is also applicable to JDK 6 Update 45 and JDK 5 Update 45 releases.

Upgrade the current Java version used by OpenEdge to the later supported version update.  Refer to Articles:
The following Java version is packed with the OpenEdge 11.4, 11.5, 11.6 installation media:
  • JDK 1.7.0_45: Windows (32-bit and 64-bit), Solaris (64-bit), Linux (32-bit and 64-bit) 
  • OpenEdge 11.6, is still shipped with Java 1.7, however Java 8 Runtime is supported on all OpenEdge 11.6 supported. Refer to Article  Java 8: Does OpenEdge Support Java8 Runtime for OE11.6?    
  • Java 8 is certified for and is the shipped version since OpenEdge 11.7.x and therefore no update is required.
To disable class-loading thus prevent the attack, open DLC/properties/ file and modify the 'jvmargs' line" under the following section to prevent 'hacking' the main AdminServer process (default port 20931)
jvmargs=....... -Djava.rmi.server.useCodebaseOnly=true

For NameServer, WebSpeed, AppServer modify the jvmargs line under their respective sections in DLC/properties/

Then restart the AdminServer.

Additional security can be added using a host-based firewall to restrict access to the affected service(s).

The OEM / OEE Console can further be secured by using SSL, disabling HTTP and switching to use HTTPS with a valid certificate. For further information refer to Article:
Last Modified Date11/20/2020 7:11 AM
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