CWE

Common Weakness Enumeration

A Community-Developed List of Software Weakness Types

CWE/SANS Top 25 Most Dangerous Software Errors
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ID

CWE-500: Public Static Field Not Marked Final

Weakness ID: 500
Abstraction: Variant
Structure: Simple
Status: Draft
Presentation Filter:
+ Description
An object contains a public static field that is not marked final, which might allow it to be modified in unexpected ways.
+ Extended Description
Public static variables can be read without an accessor and changed without a mutator by any classes in the application.
+ 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
ChildOfVariantVariant - a weakness that is described at a very low level of detail, typically limited to a specific language or technology. More specific than a Base weakness.493Critical Public Variable Without Final Modifier
+ Relevant to the view "Development Concepts" (CWE-699)
NatureTypeIDName
ChildOfVariantVariant - a weakness that is described at a very low level of detail, typically limited to a specific language or technology. More specific than a Base weakness.493Critical Public Variable Without Final Modifier
+ Background Details
When a field is declared public but not final, the field can be read and written to by arbitrary Java code.
+ 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
Implementation
+ 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

C++ (Undetermined Prevalence)

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: Modify Application Data

The object could potentially be tampered with.
Confidentiality

Technical Impact: Read Application Data

The object could potentially allow the object to be read.
+ Likelihood Of Exploit
High
+ Demonstrative Examples

Example 1

The following examples use of a public static String variable to contain the name of a property/configuration file for the application.

(bad code)
Example Language: C++ 
class SomeAppClass {

public:
static string appPropertiesConfigFile = "app/properties.config";

...
}
(bad code)
Example Language: Java 
public class SomeAppClass {

public static String appPropertiesFile = "app/Application.properties";
...
}

Having a public static variable that is not marked final (constant) may allow the variable to the altered in a way not intended by the application. In this example the String variable can be modified to indicate a different on nonexistent properties file which could cause the application to crash or caused unexpected behavior.

(good code)
Example Language: C++ 
class SomeAppClass {

public:
static const string appPropertiesConfigFile = "app/properties.config";

...
}
(good code)
Example Language: Java 
public class SomeAppClass {

public static final String appPropertiesFile = "app/Application.properties";
...
}
+ Potential Mitigations

Phase: Architecture and Design

Clearly identify the scope for all critical data elements, including whether they should be regarded as static.

Phase: Implementation

Make any static fields private and constant.

A constant field is denoted by the keyword 'const' in C/C++ and ' final' in Java

+ 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
MemberOfCategoryCategory - a CWE entry that contains a set of other entries that share a common characteristic.849CERT Java Secure Coding Section 04 - Object Orientation (OBJ)
MemberOfCategoryCategory - a CWE entry that contains a set of other entries that share a common characteristic.1002SFP Secondary Cluster: Unexpected Entry Points
+ Taxonomy Mappings
Mapped Taxonomy NameNode IDFitMapped Node Name
CLASPOverflow of static internal buffer
CERT Java Secure CodingOBJ10-JDo not use public static nonfinal variables
Software Fault PatternsSFP28Unexpected access points
+ Content History
Submissions
Submission DateSubmitterOrganization
CLASP
Modifications
Modification DateModifierOrganization
2008-07-01Eric DalciCigital
updated Time_of_Introduction
2008-08-01KDM Analytics
added/updated white box definitions
2008-09-08CWE Content TeamMITRE
updated Applicable_Platforms, Common_Consequences, Relationships, Other_Notes, Taxonomy_Mappings
2008-11-05CWE Content TeamMITRE
Significant clarification of this entry, and improved examples.
2008-11-24CWE Content TeamMITRE
updated Background_Details, Demonstrative_Examples, Description, Name, Other_Notes, Potential_Mitigations
2009-05-27CWE Content TeamMITRE
updated Relationships
2011-06-01CWE Content TeamMITRE
updated Common_Consequences, Relationships, Taxonomy_Mappings
2012-05-11CWE Content TeamMITRE
updated Relationships, Taxonomy_Mappings
2012-10-30CWE Content TeamMITRE
updated Demonstrative_Examples, Description, Potential_Mitigations
2014-07-30CWE Content TeamMITRE
updated Relationships, Taxonomy_Mappings
2017-11-08CWE Content TeamMITRE
updated White_Box_Definitions
Previous Entry Names
Change DatePrevious Entry Name
2008-04-11Overflow of Static Internal Buffer
2008-11-24Static Field Not Marked Final

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Page Last Updated: March 29, 2018