Weakness · High
CWE-762: Mismatched Memory Management Routines
What it is
The product attempts to return a memory resource to the system, but it calls a release function that is not compatible with the function that was originally used to allocate that resource.
- Severity (our rating)
- High
- Likelihood of exploit
- Low
- Introduced during
- Implementation
- Exploited in the wild
- No CVE in CISA's catalog
In more detail
This weakness can be generally described as mismatching memory management routines, such as: The memory was allocated on the stack (automatically), but it was deallocated using the memory management routine free() (CWE-590), which is intended for explicitly allocated heap memory. The memory was allocated explicitly using one set of memory management functions, and deallocated using a different set. For example, memory might be allocated with malloc() in C++ instead of the new operator, and then deallocated with the delete operator. When the memory management functions are mismatched, the consequences may be as severe as code execution, memory corruption, or program crash. Consequences and ease of exploit will vary depending on the implementation of the routines and the object being managed.
What an attacker can do
- Modify Memory (Integrity, Availability, Confidentiality)
- DoS: Crash, Exit, or Restart (Integrity, Availability, Confidentiality)
- Execute Unauthorized Code or Commands (Integrity, Availability, Confidentiality)
How to prevent it
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().
- 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). 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.
- Use a language that provides abstractions for memory allocation and deallocation.
How to find it
- Dynamic Analysis with Automated Results Interpretation. Use a tool that dynamically detects memory management problems, such as valgrind.
- Automated Dynamic Analysis. Use tools that are integrated during compilation to insert runtime error-checking mechanisms related to memory safety errors, such as AddressSanitizer (ASan) for C/C++.
H2 Security
Found it in your code?
We review where it appears, fix it with your team, and check it was not already used against you.
Talk to our teamT Academy
Stop writing it in the first place
Learn to build software and systems without weaknesses like this one, with practice on real hosts in your browser, every objective checked on the machine.
Start freeSource: MITRE Common Weakness Enumeration, CWE version 4.19.1. CWE is a trademark of The MITRE Corporation.