CWE

Common Weakness Enumeration

A Community-Developed List of Software Weakness Types

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ID

CWE-105: Struts: Form Field Without Validator

Weakness ID: 105
Abstraction: Variant
Structure: Simple
Status: Draft
Presentation Filter:
+ Description
The application has a form field that is not validated by a corresponding validation form, which can introduce other weaknesses related to insufficient input validation.
+ Extended Description
Omitting validation for even a single input field may give attackers the leeway they need to compromise the application. 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.
+ 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)
NatureTypeIDName
ChildOfClassClass20Improper Input Validation
+ Relevant to the view "Development Concepts" (CWE-699)
NatureTypeIDName
ChildOfClassClass20Improper Input Validation
+ Relevant to the view "Seven Pernicious Kingdoms" (CWE-700)
NatureTypeIDName
ChildOfClassClass20Improper Input Validation
+ 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.

PhaseNote
ImplementationSome applications use the same ActionForm for more than one purpose. In situations like this, some fields may go unused under some action mappings.
+ 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.

Languages

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.

ScopeImpactLikelihood
Integrity

Technical Impact: Unexpected State

Integrity

Technical Impact: Bypass Protection Mechanism

If unused fields are not validated, shared business logic in an action may allow attackers to bypass the validation checks that are performed for other uses of the form.
+ Demonstrative Examples

Example 1

In the following example the Java 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 in the form fields using the private member variables. The RegistrationForm class uses the Struts validation capability by extending the ValidatorForm class and including the validation for the form fields within the validator XML file, validator.xml.

(result)
 
public class RegistrationForm extends org.apache.struts.validator.ValidatorForm {
// private variables for registration form
private String name;
private String address;
private String city;
private String state;
private String zipcode;
private String phone;
private String email;

public RegistrationForm() {
super();

}
// getter and setter methods for private variables

...

}

The validator XML file, validator.xml, provides the validation for the form fields of the RegistrationForm.

(bad)
Example Language: XML 
<form-validation>
<formset>
<form name="RegistrationForm">
<field property="name" depends="required">
<arg position="0" key="prompt.name"/>

</field>
<field property="address" depends="required">
<arg position="0" key="prompt.address"/>

</field>
<field property="city" depends="required">
<arg position="0" key="prompt.city"/>

</field>
<field property="state" depends="required,mask">
<arg position="0" key="prompt.state"/>
<var>
<var-name>mask</var-name>
<var-value>[a-zA-Z]{2}</var-value>

</var>

</field>
<field property="zipcode" depends="required,mask">
<arg position="0" key="prompt.zipcode"/>
<var>
<var-name>mask</var-name>
<var-value>\d{5}</var-value>

</var>

</field>

</form>

</formset>

</form-validation>

However, in the previous example the validator XML file, validator.xml, does not provide validators for all of the form fields in the RegistrationForm. Validator forms are only provided for the first five of the seven form fields. The validator XML file should contain validator forms for all of the form fields for a Struts ActionForm bean. The following validator.xml file for the RegistrationForm class contains validator forms for all of the form fields.

(good)
Example Language: XML 
<form-validation>
<formset>
<form name="RegistrationForm">
<field property="name" depends="required">
<arg position="0" key="prompt.name"/>

</field>
<field property="address" depends="required">
<arg position="0" key="prompt.address"/>

</field>
<field property="city" depends="required">
<arg position="0" key="prompt.city"/>

</field>
<field property="state" depends="required,mask">
<arg position="0" key="prompt.state"/>
<var>
<var-name>mask</var-name>
<var-value>[a-zA-Z]{2}</var-value>

</var>

</field>
<field property="zipcode" depends="required,mask">
<arg position="0" key="prompt.zipcode"/>
<var>
<var-name>mask</var-name>
<var-value>\d{5}</var-value>

</var>

</field>
<field property="phone" depends="required,mask">
<arg position="0" key="prompt.phone"/>
<var>
<var-name>mask</var-name>
<var-value>^([0-9]{3})(-)([0-9]{4}|[0-9]{4})$</var-value>

</var>

</field>
<field property="email" depends="required,email">
<arg position="0" key="prompt.email"/>

</field>

</form>

</formset>

</form-validation>
+ Potential Mitigations

Phase: Implementation

Ensure that you validate all form fields. If a field is unused, it is still important to constrain it so that it is empty or undefined.
+ Weakness Ordinalities
OrdinalityDescription
Primary
(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.
NatureTypeIDName
MemberOfCategoryCategory990SFP Secondary Cluster: Tainted Input to Command
+ Taxonomy Mappings
Mapped Taxonomy NameNode IDFitMapped Node Name
7 Pernicious KingdomsStruts: Form Field Without Validator
Software Fault PatternsSFP24Tainted input to command
+ Content History
Submissions
Submission DateSubmitterOrganizationSource
7 Pernicious Kingdoms
Modifications
Modification DateModifierOrganizationSource
2008-07-01Eric DalciCigital
updated Time_of_Introduction
2008-09-08CWE Content TeamMITRE
updated Relationships, Other_Notes, Taxonomy_Mappings, Weakness_Ordinalities
2010-06-21CWE Content TeamMITRE
updated Demonstrative_Examples
2011-06-01CWE Content TeamMITRE
updated Common_Consequences
2011-06-27CWE Content TeamMITRE
updated Common_Consequences
2012-05-11CWE Content TeamMITRE
updated Relationships
2012-10-30CWE Content TeamMITRE
updated Potential_Mitigations
2014-06-23CWE Content TeamMITRE
updated Common_Consequences, Description, Modes_of_Introduction, Other_Notes
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: November 14, 2017