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Common Weakness Enumeration

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Home > CWE List > CWE-500: Public Static Field Not Marked Final (4.16)  
ID

CWE-500: Public Static Field Not Marked Final

Weakness ID: 500
Vulnerability Mapping: ALLOWED This CWE ID may be used to map to real-world vulnerabilities
Abstraction: Variant Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.
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+ 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.
+ Common Consequences
Section HelpThis table 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.
Scope Impact Likelihood
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.
+ 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

+ Relationships
Section Help This table 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)
Nature Type ID Name
ChildOf Variant Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource. 493 Critical 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
Section HelpThe different Modes of Introduction provide information about how and when this weakness may be introduced. The Phase identifies a point in the life cycle at which introduction may occur, while the Note provides a typical scenario related to introduction during the given phase.
Phase Note
Implementation
+ Applicable Platforms
Section HelpThis listing shows 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)

+ 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";
...
}

+ Detection Methods

Automated Static Analysis

Automated static analysis, commonly referred to as Static Application Security Testing (SAST), can find some instances of this weakness by analyzing source code (or binary/compiled code) without having to execute it. Typically, this is done by building a model of data flow and control flow, then searching for potentially-vulnerable patterns that connect "sources" (origins of input) with "sinks" (destinations where the data interacts with external components, a lower layer such as the OS, etc.)

Effectiveness: High

+ Memberships
Section HelpThis 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.
Nature Type ID Name
MemberOf CategoryCategory - a CWE entry that contains a set of other entries that share a common characteristic. 849 The CERT Oracle Secure Coding Standard for Java (2011) Chapter 6 - Object Orientation (OBJ)
MemberOf CategoryCategory - a CWE entry that contains a set of other entries that share a common characteristic. 1002 SFP Secondary Cluster: Unexpected Entry Points
MemberOf CategoryCategory - a CWE entry that contains a set of other entries that share a common characteristic. 1139 SEI CERT Oracle Secure Coding Standard for Java - Guidelines 05. Object Orientation (OBJ)
MemberOf CategoryCategory - a CWE entry that contains a set of other entries that share a common characteristic. 1403 Comprehensive Categorization: Exposed Resource
+ Vulnerability Mapping Notes

Usage: ALLOWED

(this CWE ID may be used to map to real-world vulnerabilities)

Reason: Acceptable-Use

Rationale:

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.

Comments:

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.
+ Taxonomy Mappings
Mapped Taxonomy Name Node ID Fit Mapped Node Name
CLASP Overflow of static internal buffer
The CERT Oracle Secure Coding Standard for Java (2011) OBJ10-J Do not use public static nonfinal variables
Software Fault Patterns SFP28 Unexpected access points
+ References
[REF-18] Secure Software, Inc.. "The CLASP Application Security Process". 2005. <https://cwe.mitre.org/documents/sources/TheCLASPApplicationSecurityProcess.pdf>. URL validated: 2024-11-17.
+ Content History
+ Submissions
Submission Date Submitter Organization
2006-07-19
(CWE Draft 3, 2006-07-19)
CLASP
+ Modifications
Modification Date Modifier Organization
2008-07-01 Eric Dalci Cigital
updated Time_of_Introduction
2008-08-01 KDM Analytics
added/updated white box definitions
2008-09-08 CWE Content Team MITRE
updated Applicable_Platforms, Common_Consequences, Relationships, Other_Notes, Taxonomy_Mappings
2008-11-05 CWE Content Team MITRE
Significant clarification of this entry, and improved examples.
2008-11-24 CWE Content Team MITRE
updated Background_Details, Demonstrative_Examples, Description, Name, Other_Notes, Potential_Mitigations
2009-05-27 CWE Content Team MITRE
updated Relationships
2011-06-01 CWE Content Team MITRE
updated Common_Consequences, Relationships, Taxonomy_Mappings
2012-05-11 CWE Content Team MITRE
updated Relationships, Taxonomy_Mappings
2012-10-30 CWE Content Team MITRE
updated Demonstrative_Examples, Description, Potential_Mitigations
2014-07-30 CWE Content Team MITRE
updated Relationships, Taxonomy_Mappings
2017-11-08 CWE Content Team MITRE
updated White_Box_Definitions
2019-01-03 CWE Content Team MITRE
updated Relationships, Taxonomy_Mappings
2020-02-24 CWE Content Team MITRE
updated References, Relationships
2023-04-27 CWE Content Team MITRE
updated Detection_Factors, Relationships
2023-06-29 CWE Content Team MITRE
updated Mapping_Notes
+ Previous Entry Names
Change Date Previous Entry Name
2008-04-11 Overflow of Static Internal Buffer
2008-11-24 Static Field Not Marked Final
Page Last Updated: November 19, 2024