CWE-609 Base Brouillon

Double-Checked Locking

Double-checked locking is an insufficient synchronization pattern where a program checks a resource's state, acquires a lock, and checks the state again before initialization, failing to guarantee…

Définition

What is CWE-609?

Double-checked locking is an insufficient synchronization pattern where a program checks a resource's state, acquires a lock, and checks the state again before initialization, failing to guarantee thread safety across all systems.

Double-checked locking attempts to optimize performance by avoiding the cost of synchronization on every access. A thread first checks if a resource (like an object) is initialized without a lock. If it appears uninitialized, the thread then acquires a lock, performs a second check, and only initializes the resource if the second check also confirms it's needed. This pattern aims to minimize lock contention but is fundamentally flawed. The core issue is that this sequence is not guaranteed to be atomic or visible in the same order to other threads running concurrently. Without proper synchronization on the initial check, other threads might see a partially constructed object or cache the uninitialized state, leading to unpredictable behavior and crashes. Because memory model guarantees vary across programming languages and hardware architectures, this pattern is unreliable and should be replaced with thread-safe initialization methods.

Impact réel

Real-world CVEs caused by CWE-609

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
It may seem that the following bit of code achieves thread safety while avoiding unnecessary synchronization...
2
The programmer wants to guarantee that only one Helper() object is ever allocated, but does not want to pay the cost of synchronization every time this code is called.
3
Suppose that helper is not initialized. Then, thread A sees that helper==null and enters the synchronized block and begins to execute:
4
If a second thread, thread B, takes over in the middle of this call and helper has not finished running the constructor, then thread B may make calls on helper while its fields hold incorrect values.

Exemple de code vulnérable

Vulnerable Java

It may seem that the following bit of code achieves thread safety while avoiding unnecessary synchronization...

Vulnérable Java

if (helper == null) {
  		synchronized (this) {
  			if (helper == null) {
  				helper = new Helper();
  			}
  		}
  }
  return helper;

Exemple de code sécurisé

Secure pseudo

Sécurisé pseudo

// Validate, sanitize, or use a safe API before reaching the sink.
function handleRequest(input) {
  const safe = validateAndEscape(input);
  return executeWithGuards(safe);
}

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-609

Implementation While double-checked locking can be achieved in some languages, it is inherently flawed in Java before 1.5, and cannot be achieved without compromising platform independence. Before Java 1.5, only use of the synchronized keyword is known to work. Beginning in Java 1.5, use of the "volatile" keyword allows double-checked locking to work successfully, although there is some debate as to whether it achieves sufficient performance gains. See references.

Signaux de détection

How to detect CWE-609

SAST High

Exécuter une analyse statique (SAST) sur le code source à la recherche du motif non sécurisé dans le flux de données.

DAST Moderate

Exécuter des tests de sécurité applicative dynamique (DAST) contre le point de terminaison en ligne.

Runtime Moderate

Surveiller les journaux runtime pour détecter des traces d'exception inhabituelles, des entrées malformées ou des tentatives de contournement d'autorisation.

Code review Moderate

Revue de code : signaler tout nouveau code qui traite les entrées de cette surface sans utiliser les helpers du framework validés.

Correction automatique Plexicus

Plexicus détecte automatiquement CWE-609 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.

Obtenir une démo Essayer Plexicus gratuitement

Questions fréquentes

Frequently asked questions

Qu'est-ce que CWE-609 ?

Quelle est la gravité de CWE-609 ?

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-609 ?

MITRE lists the following affected platforms: Java.

Comment puis-je prévenir CWE-609 ?

While double-checked locking can be achieved in some languages, it is inherently flawed in Java before 1.5, and cannot be achieved without compromising platform independence. Before Java 1.5, only use of the synchronized keyword is known to work. Beginning in Java 1.5, use of the "volatile" keyword allows double-checked locking to work successfully, although there is some debate as to whether it achieves sufficient performance gains. See references.

Comment Plexicus détecte et corrige CWE-609 ?

Le moteur SAST de Plexicus reconnaît la signature de flux de données de CWE-609 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-609 ?

MITRE publie la définition canonique à https://cwe.mitre.org/data/definitions/609.html. Vous pouvez également consulter la documentation OWASP et NIST pour des conseils adjacents.

Faiblesses associées

Weaknesses related to CWE-609

CWE-667 Parent

Improper Locking

This vulnerability occurs when a program fails to correctly acquire or release a lock on a shared resource, such as a file, database…

CWE-1232 Frère

Improper Lock Behavior After Power State Transition

This vulnerability occurs when a hardware lock bit, designed to protect critical system configuration registers, is improperly reset or…

CWE-1233 Frère

Security-Sensitive Hardware Controls with Missing Lock Bit Protection

This vulnerability occurs when a hardware device uses a lock bit to protect critical configuration registers, but the lock fails to…

CWE-1234 Frère

Hardware Internal or Debug Modes Allow Override of Locks

Hardware debug modes or internal states can bypass critical system lock protections, allowing unauthorized changes to device configuration.

CWE-412 Frère

Unrestricted Externally Accessible Lock

This vulnerability occurs when a system correctly checks for a lock's existence, but an unauthorized external actor can control or…

CWE-413 Frère

Improper Resource Locking

This vulnerability occurs when an application fails to properly lock a shared resource, such as a file or memory location, before…

CWE-414 Frère

Missing Lock Check

This vulnerability occurs when software fails to verify that a proper synchronization lock is active before accessing or modifying a…

CWE-764 Frère

Multiple Locks of a Critical Resource

This vulnerability occurs when a critical resource, such as a file, data structure, or connection, is locked more times than the software…

CWE-765 Frère

Multiple Unlocks of a Critical Resource

This vulnerability occurs when a critical resource, like a lock or semaphore, is unlocked more times than it was locked, putting the…

Ressources

Arrêtez de payer par développeur.
Commencez à fermer la boucle.

Plexicus est l'ASPM natif IA qui scanne, filtre, corrige, penteste et explique — de façon autonome. Développeurs illimités, dépôts illimités, actions IA à usage équitable. Vrai niveau gratuit, €269/mo annuel quand vous êtes prêt.

Commencer gratuitement Réserver une démo