Common Weakness Enumeration

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CWE-104: Struts: Form Bean Does Not Extend Validation Class

Weakness ID: 104
Abstraction: Variant
Structure: Simple
Status: Draft
Presentation Filter:
+ Description
If a form bean does not extend an ActionForm subclass of the Validator framework, it can expose the application to other weaknesses related to insufficient input validation.
+ Relationships

The table(s) below shows the weaknesses and high level categories that are related to this weakness. These relationships are defined as ChildOf, ParentOf, MemberOf and give insight to similar items that may exist at higher and lower levels of abstraction. In addition, relationships such as PeerOf and CanAlsoBe are defined to show similar weaknesses that the user may want to explore.

+ Relevant to the view "Research Concepts" (CWE-1000)
ChildOfClassClass573Improper Following of Specification by Caller
+ Relevant to the view "Development Concepts" (CWE-699)
ChildOfClassClass20Improper Input Validation
+ Relevant to the view "Seven Pernicious Kingdoms" (CWE-700)
ChildOfClassClass20Improper Input Validation
+ Background Details
In order to use the Struts Validator, a form must extend one of the following: ValidatorForm, ValidatorActionForm, DynaValidatorActionForm, and DynaValidatorForm. You must extend one of these classes because the Struts Validator ties in to your application by implementing the validate() method in these classes. Forms derived from the ActionForm and DynaActionForm classes cannot use the Struts Validator.
+ Modes Of Introduction

The different Modes of Introduction provide information about how and when this weakness may be introduced. The Phase identifies a point in the software life cycle at which introduction may occur, while the Note provides a typical scenario related to introduction during the given phase.

+ Applicable Platforms
The listings below show possible areas for which the given weakness could appear. These may be for specific named Languages, Operating Systems, Architectures, Paradigms, Technologies, or a class of such platforms. The platform is listed along with how frequently the given weakness appears for that instance.


Java (Undetermined Prevalence)

+ Common Consequences

The table below specifies different individual consequences associated with the weakness. The Scope identifies the application security area that is violated, while the Impact describes the negative technical impact that arises if an adversary succeeds in exploiting this weakness. The Likelihood provides information about how likely the specific consequence is expected to be seen relative to the other consequences in the list. For example, there may be high likelihood that a weakness will be exploited to achieve a certain impact, but a low likelihood that it will be exploited to achieve a different impact.


Technical Impact: Other

Bypassing the validation framework for a form exposes the application to numerous types of attacks. Unchecked input is an important component of vulnerabilities like cross-site scripting, process control, and SQL injection.

Technical Impact: Other

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.
+ Demonstrative Examples

Example 1

In the following Java example the class RegistrationForm is a Struts framework ActionForm Bean that will maintain user information 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.

(bad code)
Example Language: Java 
public class RegistrationForm extends org.apache.struts.action.ActionForm {
// private variables for registration form
private String name;
private String email;

public RegistrationForm() {


// getter and setter methods for private variables


However, the RegistrationForm class extends the Struts ActionForm class which does not allow the RegistrationForm class to use the Struts validator capabilities. When using the Struts framework to maintain user data in an ActionForm Bean, the class should always extend one of the validator classes, ValidatorForm, ValidatorActionForm, DynaValidatorForm or DynaValidatorActionForm. These validator classes provide default validation and the validate method for custom validation for the Bean object to use for validating input data. The following Java example shows the RegistrationForm class extending the ValidatorForm class and implementing the validate method for validating input data.

(good code)
Example Language: Java 
public class RegistrationForm extends org.apache.struts.validator.ValidatorForm {
// private variables for registration form
private String name;
private String email;

public RegistrationForm() {


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

// getter and setter methods for private variables


Note that the ValidatorForm class itself extends the ActionForm class within the Struts framework API.

+ Potential Mitigations

Phase: Implementation

Ensure that all forms extend one of the Validation Classes.
+ Weakness Ordinalities
(where the weakness exists independent of other weaknesses)
+ Memberships
This MemberOf Relationships table shows additional CWE Categories and Views that reference this weakness as a member. This information is often useful in understanding where a weakness fits within the context of external information sources.
+ Taxonomy Mappings
Mapped Taxonomy NameNode IDFitMapped Node Name
7 Pernicious KingdomsStruts: Form Bean Does Not Extend Validation Class
Software Fault PatternsSFP24Tainted input to command
+ Content History
Submission DateSubmitterOrganization
7 Pernicious Kingdoms
Modification DateModifierOrganization
2008-07-01Eric DalciCigital
updated Potential_Mitigations, Time_of_Introduction
2008-09-08CWE Content TeamMITRE
updated Relationships, Other_Notes, Taxonomy_Mappings, Weakness_Ordinalities
2008-11-24CWE Content TeamMITRE
updated Background_Details, Common_Consequences, Other_Notes
2009-03-10CWE Content TeamMITRE
updated Relationships
2009-12-28CWE Content TeamMITRE
updated Common_Consequences, Other_Notes
2010-06-21CWE Content TeamMITRE
updated Demonstrative_Examples
2011-06-01CWE Content TeamMITRE
updated Common_Consequences
2012-05-11CWE Content TeamMITRE
updated Relationships
2012-10-30CWE Content TeamMITRE
updated Potential_Mitigations
2014-07-30CWE Content TeamMITRE
updated Relationships, Taxonomy_Mappings
2017-11-08CWE Content TeamMITRE
updated Causal_Nature, Relationships

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Page Last Updated: January 18, 2018