Remote Java Code Execution in MVEL
CVE: CVE-2013-6468
Component: Drools
Severity: Important
Release date: 2013-01-01T00:00:00+00:00

JBoss Drools, Red Hat JBoss BRMS before 6.0.1, and Red Hat JBoss BPM Suite before 6.0.1 allows remote authenticated users to execute arbitrary Java code via a (1) MVFLEX Expression Language (MVEL) or (2) Drools expression.


Remediation:
The References section of this erratum contains download links (you must
log in to download the updates). Before applying the update, back up your
existing installation, including all applications, configuration files,
databases and database settings, and so on.

It is recommended to halt the server by stopping the JBoss Application
Server process before installing this update, and then after installing the
update, restart the server by starting the JBoss Application Server process.

The fix for CVE-2013-6468 enables the Java Security Manager (JSM) to
sandbox the evaluation of MVEL expressions. This introduces performance
degradation in high load environments. The following ways of running Red
Hat JBoss BPM Suite are considered secure while mitigating performance
degradation:

1. In high load environments where performance is critical, it is
recommended to only deploy applications that have been developed on other
systems and properly reviewed. It is also recommended not to create any
users with the Analyst role on such systems. If these safeguards are
followed, it is safe to leave JSM disabled on these systems so it does not
introduce any performance degradation.

2. In testing and development environments without high loads, or in
environments where rule authoring is exposed to external networks, it is
recommended to have JSM enabled in order to achieve security benefits of
properly sandboxed evaluation of MVEL expressions.

Allowing users with the Analyst role to log in to the Business Central
console when JSM is disabled is not secure and not recommended.
The References section of this erratum contains download links (you must
log in to download the updates). Before applying the update, back up your
existing installation, including all applications, configuration files,
databases and database settings, and so on.

It is recommended to halt the server by stopping the JBoss Application
Server process before installing this update, and then after installing the
update, restart the server by starting the JBoss Application Server process.

The fix for CVE-2013-6468 enables the Java Security Manager (JSM) to
sandbox the evaluation of MVEL expressions. This introduces performance
degradation in high load environments. The following ways of running Red
Hat JBoss BRMS are considered secure while mitigating performance
degradation:

1. In high load environments where performance is critical, it is
recommended to only deploy applications that have been developed on other
systems and properly reviewed. It is also recommended not to create any
users with the Analyst role on such systems. If these safeguards are
followed, it is safe to leave JSM disabled on these systems so it does not
introduce any performance degradation.

2. In testing and development environments without high loads, or in
environments where rule authoring is exposed to external networks, it is
recommended to have JSM enabled in order to achieve security benefits of
properly sandboxed evaluation of MVEL expressions.

Allowing users with the Analyst role to log in to the Business Central
console when JSM is disabled is not secure and not recommended.