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-766 Base Incomplet
Critical Data Element Declared Public
This vulnerability occurs when a critical piece of data—like a variable, field, or class member—is mistakenly declared as public when it should be kept private according to the application's…
Définition
What is CWE-766?
This vulnerability occurs when a critical piece of data—like a variable, field, or class member—is mistakenly declared as public when it should be kept private according to the application's security design.
Declaring sensitive data as public breaks fundamental security principles like encapsulation and least privilege. It directly exposes critical information, such as internal state, configuration secrets, or authentication tokens, to any other part of the codebase or, in some languages and contexts, to external actors. This creates a clear and immediate attack surface, making it trivial for an attacker to read or modify data that should be strictly controlled.
Beyond the direct security flaw, this practice severely damages code maintainability and security hygiene. It becomes difficult to track how and where this critical data is being used or altered, scattering logic that should be centralized. This "spaghetti code" effect makes identifying the root cause of bugs or vulnerabilities more time-consuming and increases the risk of introducing new security weaknesses during future development or refactoring.
Impact réel
Real-world CVEs caused by CWE-766
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variables declared public allow remote read of system properties such as user name and home directory.
Comment les attaquants l'exploitent
Parcours de l'attaquant étape par étape
- 1
The following example declares a critical variable public, making it accessible to anyone with access to the object in which it is contained.
- 2
Instead, the critical data should be declared private.
- 3
Even though this example declares the password to be private, there are other possible issues with this implementation, such as the possibility of recovering the password from process memory (CWE-257).
- 4
The following example shows a basic user account class that includes member variables for the username and password as well as a public constructor for the class and a public method to authorize access to the user account.
- 5
However, the member variables username and password are declared public and therefore will allow access and changes to the member variables to anyone with access to the object. These member variables should be declared private as shown below to prevent unauthorized access and changes.
Exemple de code vulnérable
Vulnerable C++
The following example declares a critical variable public, making it accessible to anyone with access to the object in which it is contained.
public: char* password; Exemple de code sécurisé
Secure C++
Instead, the critical data should be declared private.
private: char* password; 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-766
- Implementation Data should be private, static, and final whenever possible. This will assure that your code is protected by instantiating early, preventing access, and preventing tampering.
Signaux de détection
How to detect CWE-766
Plexicus détecte automatiquement CWE-766 et ouvre une PR de correction en moins de 60 secondes.
Codex Remedium analyse chaque commit, identifie cette faiblesse précise et livre une pull request prête à être relue avec le correctif. Pas de tickets. Pas de transferts.
Questions fréquentes Qu'est-ce que CWE-766 ?
Quelle est la gravité de CWE-766 ?
Quels langages ou plateformes sont affectés par CWE-766 ?
Comment puis-je prévenir CWE-766 ?
Comment Plexicus détecte et corrige CWE-766 ?
Où puis-je en savoir plus sur CWE-766 ?
Frequently asked questions
Qu'est-ce que CWE-766 ?
This vulnerability occurs when a critical piece of data—like a variable, field, or class member—is mistakenly declared as public when it should be kept private according to the application's security design.
Quelle est la gravité de CWE-766 ?
MITRE n'a pas publié de note de probabilité d'exploitation pour cette faiblesse. Traitez-la comme un impact moyen jusqu'à ce que votre modèle de menace prouve le contraire.
Quels langages ou plateformes sont affectés par CWE-766 ?
MITRE lists the following affected platforms: C++, C#, Java.
Comment puis-je prévenir CWE-766 ?
Data should be private, static, and final whenever possible. This will assure that your code is protected by instantiating early, preventing access, and preventing tampering.
Comment Plexicus détecte et corrige CWE-766 ?
Le moteur SAST de Plexicus reconnaît la signature de flux de données de CWE-766 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-766 ?
MITRE publie la définition canonique à https://cwe.mitre.org/data/definitions/766.html. Vous pouvez également consulter la documentation OWASP et NIST pour des conseils adjacents.
Faiblesses associées
Weaknesses related to CWE-766
CWE-732 Parent
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Improper Preservation of Permissions
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