EJB Bad Practices: Use of Class Loader

Draft Variant

Structure: Simple

Description

The product violates the Enterprise JavaBeans (EJB) specification by using the class loader.

Extended Description

The Enterprise JavaBeans specification requires that every bean provider follow a set of programming guidelines designed to ensure that the bean will be portable and behave consistently in any EJB container. In this case, the product violates the following EJB guideline: "The enterprise bean must not attempt to create a class loader; obtain the current class loader; set the context class loader; set security manager; create a new security manager; stop the JVM; or change the input, output, and error streams." The specification justifies this requirement in the following way: "These functions are reserved for the EJB container. Allowing the enterprise bean to use these functions could compromise security and decrease the container's ability to properly manage the runtime environment."

Common Consequences 1

Scope: ConfidentialityIntegrityAvailabilityOther

Impact: Execute Unauthorized Code or CommandsVaries by Context

Potential Mitigations 1

Phase: Architecture and DesignImplementation

Do not use the Class Loader when writing EJBs.

Demonstrative Examples 2

The following Java example is a simple stateless Enterprise JavaBean that retrieves the interest rate for the number of points for a mortgage. The interest rates for various points are retrieved from an XML document on the local file system, and the EJB uses the Class Loader for the EJB class to obtain the XML document from the local file system as an input stream.

Code Example:

Bad

Java

java

// get XML document from the local filesystem as an input stream*

java

java

This use of the Java Class Loader class within any kind of Enterprise JavaBean violates the restriction of the EJB specification against obtaining the current class loader as this could compromise the security of the application using the EJB.

An EJB is also restricted from creating a custom class loader and creating a class and instance of a class from the class loader, as shown in the following example.

Code Example:Bad
Java
java

Applicable Platforms

Languages:

Java : Undetermined

Modes of Introduction

Implementation

Related Weaknesses

ChildOf:

Improper Following of Specification by Caller (CWE-573)

Taxonomy Mapping

Software Fault Patterns