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.)
CWE-500 Variante Brouillon
Public Static Field Not Marked Final
This vulnerability occurs when a class exposes a public static field without declaring it as final, allowing unintended modification from anywhere in the application.
Définition
What is CWE-500?
This vulnerability occurs when a class exposes a public static field without declaring it as final, allowing unintended modification from anywhere in the application.
Public static fields act as global variables within your application's classloader. Because they are public, any other class can directly read and, crucially, modify their value without using proper getter or setter methods. This bypasses any validation, logging, or synchronization logic you might have in place, leading to unpredictable state changes that are difficult to trace and debug.
To prevent this, you should mark any necessary public static fields as `final` to make them constants. If a field truly needs to be mutable, consider making it private and providing controlled access through static methods, applying the principle of encapsulation even to static members to maintain data integrity and thread safety.
Impact réel
Real-world CVEs caused by CWE-500
Aucune référence CVE publique n'est liée à ce CWE dans le catalogue MITRE pour le moment.
Comment les attaquants l'exploitent
Parcours de l'attaquant étape par étape
- 1
Identifier un chemin de code qui traite des entrées non fiables sans validation.
- 2
Élaborer une charge utile qui exploite le comportement non sécurisé — injection, traversal, débordement ou abus de logique.
- 3
Délivrer la charge utile via une requête normale et observer la réaction de l'application.
- 4
Itérer jusqu'à ce que la réponse divulgue des données, exécute le code de l'attaquant ou élève les privilèges.
Exemple de code vulnérable
Vulnerable C++
The following examples use of a public static String variable to contain the name of a property/configuration file for the application.
class SomeAppClass {
public:
static string appPropertiesConfigFile = "app/properties.config";
...
} Exemple de code sécurisé
Secure C++
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.
class SomeAppClass {
public:
static const string appPropertiesConfigFile = "app/properties.config";
...
} What changed: the unsafe sink is replaced (or the input is validated/escaped) so the same payload no longer triggers the weakness.
Liste de contrôle de prévention
How to prevent CWE-500
- Architecture and Design Clearly identify the scope for all critical data elements, including whether they should be regarded as static.
- Implementation Make any static fields private and constant. A constant field is denoted by the keyword 'const' in C/C++ and ' final' in Java
Signaux de détection
How to detect CWE-500
CWE-500
Don't catalog this weakness. Prove it's reachable.
Plexicus turns CWE catalogs into evidence: every CWE-pattern is matched against your real code graph, reach is proven on a sandbox clone, and verified findings ship as reviewed PRs.
Questions fréquentes Qu'est-ce que CWE-500 ?
Quelle est la gravité de CWE-500 ?
Quels langages ou plateformes sont affectés par CWE-500 ?
Comment puis-je prévenir CWE-500 ?
Comment Plexicus détecte et corrige CWE-500 ?
Où puis-je en savoir plus sur CWE-500 ?
Frequently asked questions
Qu'est-ce que CWE-500 ?
This vulnerability occurs when a class exposes a public static field without declaring it as final, allowing unintended modification from anywhere in the application.
Quelle est la gravité de CWE-500 ?
MITRE évalue la probabilité d'exploitation comme Élevée — cette faiblesse est activement exploitée et doit être priorisée pour la remédiation.
Quels langages ou plateformes sont affectés par CWE-500 ?
MITRE lists the following affected platforms: C++, Java.
Comment puis-je prévenir CWE-500 ?
Clearly identify the scope for all critical data elements, including whether they should be regarded as static. Make any static fields private and constant. A constant field is denoted by the keyword 'const' in C/C++ and ' final' in Java
Comment Plexicus détecte et corrige CWE-500 ?
Le moteur SAST de Plexicus reconnaît la signature de flux de données de CWE-500 à chaque commit. Lorsqu'une correspondance est trouvée, notre agent Codex Remedium ouvre une PR de correction avec le code corrigé, les tests et un résumé d'une ligne pour le relecteur.
Où puis-je en savoir plus sur CWE-500 ?
MITRE publie la définition canonique à https://cwe.mitre.org/data/definitions/500.html. Vous pouvez également consulter la documentation OWASP et NIST pour des conseils adjacents.
Faiblesses associées
Weaknesses related to CWE-500
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