Struts: Plug-in Framework not in Use

When an application does not use an input validation framework such as the Struts Validator, there is a greater risk of introducing weaknesses related to insufficient input validation.


Description

Unchecked input is the leading cause of vulnerabilities in J2EE applications. Unchecked input leads to cross-site scripting, process control, and SQL injection vulnerabilities, among others.

Although J2EE applications are not generally susceptible to memory corruption attacks, if a J2EE application interfaces with native code that does not perform array bounds checking, an attacker may be able to use an input validation mistake in the J2EE application to launch a buffer overflow attack.

Demonstrations

The following examples help to illustrate the nature of this weakness and describe methods or techniques which can be used to mitigate the risk.

Note that the examples here are by no means exhaustive and any given weakness may have many subtle varieties, each of which may require different detection methods or runtime controls.

Example One

In the following Java example the class RegistrationForm is a Struts framework ActionForm Bean that will maintain user input data from a registration webpage for an online business site. The user will enter registration data and, through the Struts framework, the RegistrationForm bean will maintain the user data.

public class RegistrationForm extends org.apache.struts.action.ActionForm {

  // private variables for registration form
  private String name;
  private String email;
  ...

  public RegistrationForm() {
    super();
  }

  // getter and setter methods for private variables
  ...

}

However, the RegistrationForm class extends the Struts ActionForm class which does use the Struts validator plug-in to provide validator capabilities. In the following example, the RegistrationForm Java class extends the ValidatorForm and Struts configuration XML file, struts-config.xml, instructs the application to use the Struts validator plug-in.

public class RegistrationForm extends org.apache.struts.validator.ValidatorForm {

  // private variables for registration form
  private String name;
  private String email;
  ...

  public RegistrationForm() {
    super();
  }

  public ActionErrors validate(ActionMapping mapping, HttpServletRequest request) {...}

  // getter and setter methods for private variables
  ...

}

The plug-in tag of the Struts configuration XML file includes the name of the validator plug-in to be used and includes a set-property tag to instruct the application to use the file, validator-rules.xml, for default validation rules and the file, validation.XML, for custom validation.

<struts-config>

  <form-beans>
    <form-bean name="RegistrationForm" type="RegistrationForm"/>
  </form-beans>

  ...

  <!-- ========================= Validator plugin ================================= -->
  <plug-in className="org.apache.struts.validator.ValidatorPlugIn">
    <set-property
      property="pathnames"
      value="/WEB-INF/validator-rules.xml,/WEB-INF/validation.xml"/>

  </plug-in>

</struts-config>

See Also

SFP Secondary Cluster: Tainted Input to Command

This category identifies Software Fault Patterns (SFPs) within the Tainted Input to Command cluster (SFP24).

Comprehensive CWE Dictionary

This view (slice) covers all the elements in CWE.

Weaknesses without Software Fault Patterns

CWE identifiers in this view are weaknesses that do not have associated Software Fault Patterns (SFPs), as covered by the CWE-888 view. As such, they represent gaps in...

Weaknesses Introduced During Implementation

This view (slice) lists weaknesses that can be introduced during implementation.


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