CWE-670 Classe Brouillon

Always-Incorrect Control Flow Implementation

This weakness occurs when a section of code is structured in a way that always executes incorrectly, regardless of input or conditions. The control flow logic is fundamentally flawed and does not…

Définition

What is CWE-670?

This weakness occurs when a section of code is structured in a way that always executes incorrectly, regardless of input or conditions. The control flow logic is fundamentally flawed and does not match the intended algorithm.

Unlike many security flaws that are triggered by unexpected or malicious data, this issue represents a permanent logic error in the code. The problematic path is always wrong, meaning the software will behave incorrectly every time that specific code segment runs. This is often the result of simple syntactic mistakes, like omitting curly braces in C-style languages, which changes which statements are included in a conditional block. For developers, this means the bug is not situational; it's a constant defect in the program's logic. Identifying these flaws requires carefully reviewing the intended algorithm against the actual code structure, as standard testing with varied inputs might not reveal the root cause—the logic itself is broken from the start.

Impact réel

Real-world CVEs caused by CWE-670

CVE-2021-3011

virtual interrupt controller in a virtualization product allows crash of host by writing a certain invalid value to a register, which triggers a fatal error instead of returning an error code

Comment les attaquants l'exploitent

Parcours de l'attaquant étape par étape

1
This code queries a server and displays its status when a request comes from an authorized IP address.
2
This code redirects unauthorized users, but continues to execute code after calling http_redirect(). This means even unauthorized users may be able to access the contents of the page or perform a DoS attack on the server being queried. Also, note that this code is vulnerable to an IP address spoofing attack (CWE-212).
3
In this example, the programmer has indented the statements to call Do_X() and Do_Y(), as if the intention is that these functions are only called when the condition is true. However, because there are no braces to signify the block, Do_Y() will always be executed, even if the condition is false.
4
This might not be what the programmer intended. When the condition is critical for security, such as in making a security decision or detecting a critical error, this may produce a vulnerability.
5
In both of these examples, a message is printed based on the month passed into the function:

Exemple de code vulnérable

Vulnerable PHP

This code queries a server and displays its status when a request comes from an authorized IP address.

Vulnérable PHP

$requestingIP = $_SERVER['REMOTE_ADDR'];
  if(!in_array($requestingIP,$ipAllowList)){
  	echo "You are not authorized to view this page";
  	http_redirect($errorPageURL);
  }
  $status = getServerStatus();
  echo $status;
```
...*

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-670

Architecture Use safe-by-default frameworks and APIs that prevent the unsafe pattern from being expressible.
Implementation Validate input at trust boundaries; use allowlists, not denylists.
Implementation Apply the principle of least privilege to credentials, file paths, and runtime permissions.
Testing Cover this weakness in CI: SAST rules + targeted unit tests for the data flow.
Operation Monitor logs for the runtime signals listed in the next section.

Signaux de détection

How to detect CWE-670

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-670 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-670 ?

Quelle est la gravité de CWE-670 ?

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-670 ?

MITRE n'a pas spécifié les plateformes affectées pour ce CWE — il peut s'appliquer à la plupart des stacks applicatives.

Comment puis-je prévenir CWE-670 ?

Use safe-by-default frameworks, validate untrusted input at trust boundaries, and apply the principle of least privilege. Cover the data-flow signature in CI with SAST.

Comment Plexicus détecte et corrige CWE-670 ?

Le moteur SAST de Plexicus reconnaît la signature de flux de données de CWE-670 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-670 ?

MITRE publie la définition canonique à https://cwe.mitre.org/data/definitions/670.html. Vous pouvez également consulter la documentation OWASP et NIST pour des conseils adjacents.

Faiblesses associées

Weaknesses related to CWE-670

CWE-691 Parent

Insufficient Control Flow Management

This vulnerability occurs when a program's execution flow isn't properly managed, allowing attackers to bypass critical checks, trigger…

CWE-1265 Frère

Unintended Reentrant Invocation of Non-reentrant Code Via Nested Calls

This vulnerability occurs when a non-reentrant function is called, and during its execution, another call is triggered that unexpectedly…

CWE-1281 Frère

Sequence of Processor Instructions Leads to Unexpected Behavior

Certain sequences of valid and invalid processor instructions can cause the CPU to lock up or behave unpredictably, often requiring a hard…

CWE-362 Frère

Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')

A race condition occurs when multiple processes or threads access a shared resource simultaneously without proper coordination, creating a…

CWE-430 Frère

Deployment of Wrong Handler

This vulnerability occurs when a system incorrectly assigns or routes an object to the wrong processing component.

CWE-431 Frère

Missing Handler

This vulnerability occurs when a software component lacks the necessary code to properly handle an error or unexpected event.

CWE-662 Frère

Improper Synchronization

This vulnerability occurs when a multi-threaded or multi-process application allows shared resources to be accessed by multiple threads or…

CWE-696 Frère

Incorrect Behavior Order

This weakness occurs when a system executes multiple dependent actions in the wrong sequence, leading to unexpected and potentially…

CWE-705 Frère

Incorrect Control Flow Scoping

This vulnerability occurs when a program fails to return execution to the correct point in the code after finishing a specific operation…

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