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CWE-762 Variante Incomplet
Mismatched Memory Management Routines
This vulnerability occurs when a program uses incompatible functions to allocate and free memory. For example, freeing memory with a function that doesn't match the one used to create it, like…
Définition
What is CWE-762?
This vulnerability occurs when a program uses incompatible functions to allocate and free memory. For example, freeing memory with a function that doesn't match the one used to create it, like mixing different memory management systems.
Mismatched memory management happens when allocation and deallocation routines come from incompatible sources. Common examples include trying to free stack-allocated memory with `free()` (which only works for heap memory), or allocating with C's `malloc()` but deallocating with C++'s `delete` operator. These functions manage memory in fundamentally different ways, and swapping them breaks the underlying memory manager's expectations.
The consequences range from immediate crashes and data corruption to more severe security issues like memory corruption exploits that could lead to arbitrary code execution. The severity depends on the specific routines involved, the program's memory layout, and whether an attacker can control or influence the mismatched operation.
Impact réel
Real-world CVEs caused by CWE-762
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
This example allocates a BarObj object using the new operator in C++, however, the programmer then deallocates the object using free(), which may lead to unexpected behavior.
- 2
Instead, the programmer should have either created the object with one of the malloc family functions, or else deleted the object with the delete operator.
- 3
In this example, the program does not use matching functions such as malloc/free, new/delete, and new[]/delete[] to allocate/deallocate the resource.
- 4
In this example, the program calls the delete[] function on non-heap memory.
Exemple de code vulnérable
Vulnerable C++
This example allocates a BarObj object using the new operator in C++, however, the programmer then deallocates the object using free(), which may lead to unexpected behavior.
void foo(){
BarObj *ptr = new BarObj()
```
/* do some work with ptr here */*
...
free(ptr);} Exemple de code sécurisé
Secure C++
Instead, the programmer should have either created the object with one of the malloc family functions, or else deleted the object with the delete operator.
void foo(){
BarObj *ptr = new BarObj()
```
/* do some work with ptr here */*
...
delete ptr;} 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-762
- Implementation Only call matching memory management functions. Do not mix and match routines. For example, when you allocate a buffer with malloc(), dispose of the original pointer with free().
- Implementation Choose a language or tool that provides automatic memory management, or makes manual memory management less error-prone. For example, glibc in Linux provides protection against free of invalid pointers. When using Xcode to target OS X or iOS, enable automatic reference counting (ARC) [REF-391]. To help correctly and consistently manage memory when programming in C++, consider using a smart pointer class such as std::auto_ptr (defined by ISO/IEC ISO/IEC 14882:2003), std::shared_ptr and std::unique_ptr (specified by an upcoming revision of the C++ standard, informally referred to as C++ 1x), or equivalent solutions such as Boost.
- Architecture and Design Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. For example, glibc in Linux provides protection against free of invalid pointers.
- Architecture and Design Use a language that provides abstractions for memory allocation and deallocation.
- Testing Use a tool that dynamically detects memory management problems, such as valgrind.
Signaux de détection
How to detect CWE-762
Exécuter des tests de sécurité applicative dynamique (DAST) contre le point de terminaison en ligne.
Surveiller les journaux runtime pour détecter des traces d'exception inhabituelles, des entrées malformées ou des tentatives de contournement d'autorisation.
Revue de code : signaler tout nouveau code qui traite les entrées de cette surface sans utiliser les helpers du framework validés.
CWE-762
Don't catalog this weakness. Prove it's reachable.
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Questions fréquentes Qu'est-ce que CWE-762 ?
Quelle est la gravité de CWE-762 ?
Quels langages ou plateformes sont affectés par CWE-762 ?
Comment puis-je prévenir CWE-762 ?
Comment Plexicus détecte et corrige CWE-762 ?
Où puis-je en savoir plus sur CWE-762 ?
Frequently asked questions
Qu'est-ce que CWE-762 ?
This vulnerability occurs when a program uses incompatible functions to allocate and free memory. For example, freeing memory with a function that doesn't match the one used to create it, like mixing different memory management systems.
Quelle est la gravité de CWE-762 ?
MITRE évalue la probabilité d'exploitation comme Faible — l'exploitation est rare, mais la faiblesse doit tout de même être corrigée lorsqu'elle est découverte.
Quels langages ou plateformes sont affectés par CWE-762 ?
MITRE lists the following affected platforms: C, C++.
Comment puis-je prévenir CWE-762 ?
Only call matching memory management functions. Do not mix and match routines. For example, when you allocate a buffer with malloc(), dispose of the original pointer with free(). Choose a language or tool that provides automatic memory management, or makes manual memory management less error-prone. For example, glibc in Linux provides protection against free of invalid pointers. When using Xcode to target OS X or iOS, enable automatic reference counting (ARC) [REF-391]. To help correctly and…
Comment Plexicus détecte et corrige CWE-762 ?
Le moteur SAST de Plexicus reconnaît la signature de flux de données de CWE-762 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-762 ?
MITRE publie la définition canonique à https://cwe.mitre.org/data/definitions/762.html. Vous pouvez également consulter la documentation OWASP et NIST pour des conseils adjacents.
Faiblesses associées
Weaknesses related to CWE-762
CWE-763 Parent
Release of Invalid Pointer or Reference
This vulnerability occurs when a program tries to free a memory resource back to the system but uses an incorrect deallocation method or…
CWE-761 Frère
Free of Pointer not at Start of Buffer
This vulnerability occurs when a program incorrectly frees a memory pointer that no longer points to the beginning of the allocated heap…
CWE-590 Enfant
Free of Memory not on the Heap
This vulnerability occurs when a program calls free() on a memory pointer that wasn't originally allocated using standard heap functions…
Ressources
Further reading
- MITRE — CWE-762 officiel https://cwe.mitre.org/data/definitions/762.html
- boost C++ Library Smart Pointers https://www.boost.org/doc/libs/1_38_0/libs/smart_ptr/smart_ptr.htm
- Valgrind https://valgrind.org/
- Transitioning to ARC Release Notes https://developer.apple.com/library/archive/releasenotes/ObjectiveC/RN-TransitioningToARC/Introduction/Introduction.html
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