Fuzz testing (fuzzing) is a powerful technique for generating large numbers of diverse inputs - either randomly or algorithmically - and dynamically invoking the code with those inputs. Even with random inputs, it is often capable of generating unexpected results such as crashes, memory corruption, or resource consumption. Fuzzing effectively produces repeatable test cases that clearly indicate bugs, which helps developers to diagnose the issues.
CWE-758 Classe Incomplet
Reliance on Undefined, Unspecified, or Implementation-Defined Behavior
This weakness occurs when software depends on specific behaviors of an API, data structure, or system component that are not formally guaranteed by its specification. The code assumes these…
Définition
What is CWE-758?
This weakness occurs when software depends on specific behaviors of an API, data structure, or system component that are not formally guaranteed by its specification. The code assumes these behaviors will always work a certain way, but they might change or fail under different conditions.
Relying on undefined or platform-specific behavior creates fragile code that can break unexpectedly. For example, a function might return results in a particular order on your development machine, but a different compiler or operating system version could alter that order, causing logic errors or crashes.
This often surfaces during porting to a new environment or during complex interactions between components. To avoid this, developers should strictly use documented, standardized behaviors and avoid assumptions about internal implementation details that aren't part of the official contract.
Impact réel
Real-world CVEs caused by CWE-758
-
Change in C compiler behavior causes resultant buffer overflows in programs that depend on behaviors that were undefined in the C standard.
Comment les attaquants l'exploitent
Parcours de l'attaquant étape par étape
- 1
This code assumes a particular function will always be found at a particular address. It assigns a pointer to that address and calls the function.
- 2
The same function may not always be found at the same memory address. This could lead to a crash, or an attacker may alter the memory at the expected address, leading to arbitrary code execution.
- 3
The following function returns a stack address.
Exemple de code vulnérable
Vulnerable C
This code assumes a particular function will always be found at a particular address. It assigns a pointer to that address and calls the function.
int (*pt2Function) (float, char, char)=0x08040000;
int result2 = (*pt2Function) (12, 'a', 'b');
```
// Here we can inject code to execute.* Exemple de code sécurisé
Secure 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-758
- 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-758
Plexicus détecte automatiquement CWE-758 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-758 ?
Quelle est la gravité de CWE-758 ?
Quels langages ou plateformes sont affectés par CWE-758 ?
Comment puis-je prévenir CWE-758 ?
Comment Plexicus détecte et corrige CWE-758 ?
Où puis-je en savoir plus sur CWE-758 ?
Frequently asked questions
Qu'est-ce que CWE-758 ?
This weakness occurs when software depends on specific behaviors of an API, data structure, or system component that are not formally guaranteed by its specification. The code assumes these behaviors will always work a certain way, but they might change or fail under different conditions.
Quelle est la gravité de CWE-758 ?
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-758 ?
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-758 ?
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-758 ?
Le moteur SAST de Plexicus reconnaît la signature de flux de données de CWE-758 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-758 ?
MITRE publie la définition canonique à https://cwe.mitre.org/data/definitions/758.html. Vous pouvez également consulter la documentation OWASP et NIST pour des conseils adjacents.
Faiblesses associées
Weaknesses related to CWE-758
CWE-710 Parent
Improper Adherence to Coding Standards
This weakness occurs when developers don't consistently follow established coding standards and best practices, which can introduce…
CWE-1041 Frère
Use of Redundant Code
This weakness occurs when a codebase contains identical or nearly identical logic duplicated across multiple functions, methods, or…
CWE-1044 Frère
Architecture with Number of Horizontal Layers Outside of Expected Range
This occurs when a software system is built with either too many or too few distinct architectural layers, falling outside a recommended…
CWE-1048 Frère
Invokable Control Element with Large Number of Outward Calls
This weakness occurs when a single function, method, or callable code block makes an excessively high number of calls to other objects or…
CWE-1059 Frère
Insufficient Technical Documentation
This weakness occurs when a software or hardware product lacks comprehensive technical documentation. Missing or incomplete details about…
CWE-1061 Frère
Insufficient Encapsulation
This weakness occurs when a software component exposes too much of its internal workings, such as data structures or implementation logic.…
CWE-1065 Frère
Runtime Resource Management Control Element in a Component Built to Run on Application Servers
This weakness occurs when an application built to run on a managed application server bypasses the server's high-level APIs and instead…
CWE-1066 Frère
Missing Serialization Control Element
This weakness occurs when a class or data structure is marked as serializable but lacks the required control methods to properly handle…
CWE-1068 Frère
Inconsistency Between Implementation and Documented Design
This weakness occurs when the actual code implementation deviates from the intended design described in its official documentation,…
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