The product has a form field that is not validated by a corresponding validation form, which can introduce other weaknesses related to insufficient input validation.
Omitting validation for even a single input field may give attackers the leeway they need to compromise the product. 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.

Primary

Implementation
Some products use the same ActionForm for more than one purpose. In situations like this, some fields may go unused under some action mappings.

Integrity
Unexpected State

Integrity
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.

Implementation
Validate all form fields. If a field is unused, it is still important to constrain it so that it is empty or undefined.

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.

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.

<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.

<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>

Struts: Form Field Without Validator

SFP24
Tainted input to command

Allowed
This CWE entry is at the Variant level of abstraction, which is a preferred level of abstraction for mapping to the root causes of vulnerabilities.
Carefully read both the name and description to ensure that this mapping is an appropriate fit. Do not try to 'force' a mapping to a lower-level Base/Variant simply to comply with this preferred level of abstraction.

7 Pernicious Kingdoms
2006-07-19
Draft 3
2006-07-19

Eric Dalci
Cigital
2008-07-01
updated Time_of_Introduction

CWE Content Team
MITRE
2008-09-08
updated Relationships, Other_Notes, Taxonomy_Mappings, Weakness_Ordinalities

CWE Content Team
MITRE
2010-06-21
updated Demonstrative_Examples

CWE Content Team
MITRE
2011-06-01
updated Common_Consequences

CWE Content Team
MITRE
2011-06-27
updated Common_Consequences

CWE Content Team
MITRE
2012-05-11
updated Relationships

CWE Content Team
MITRE
2012-10-30
updated Potential_Mitigations

CWE Content Team
MITRE
2014-06-23
updated Common_Consequences, Description, Modes_of_Introduction, Other_Notes

CWE Content Team
MITRE
2014-07-30
updated Relationships, Taxonomy_Mappings

CWE Content Team
MITRE
2017-11-08
updated Causal_Nature, Relationships

CWE Content Team
MITRE
2019-01-03
updated Relationships

CWE Content Team
MITRE
2020-02-24
updated References, Relationships

CWE Content Team
MITRE
2021-07-20
updated Potential_Mitigations

CWE Content Team
MITRE
2023-01-31
updated Description, Modes_of_Introduction

CWE Content Team
MITRE
2023-04-27
updated Relationships

CWE Content Team
MITRE
2023-06-29
updated Mapping_Notes