Free of Memory not on the Heap

Opis

The product calls free() on a pointer to memory that was not allocated using associated heap allocation functions such as malloc(), calloc(), or realloc().

When free() is called on an invalid pointer, the program's memory management data structures may become corrupted. This corruption can cause the program to crash or, in some circumstances, an attacker may be able to cause free() to operate on controllable memory locations to modify critical program variables or execute code.

Skutki

• Integrity, Confidentiality, Availability

  Execute Unauthorized Code or Commands; Modify Memory

  There is the potential for arbitrary code execution with privileges of the vulnerable program via a "write, what where" primitive. If pointers to memory which hold user information are freed, a malicious user will be able to write 4 bytes anywhere in memory.

Zapobieganie

• Implementation

  Only free pointers that you have called malloc on previously. This is the recommended solution. Keep track of which pointers point at the beginning of valid chunks and free them only once.

• Implementation

  Before freeing a pointer, the programmer should make sure that the pointer was previously allocated on the heap and that the memory belongs to the programmer. Freeing an unallocated pointer will cause undefined behavior in the program.

• Architecture and Design · Libraries or Frameworks

  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.

Przykłady podatności

• CVE-2023-22291 parser for a word processor attempts to free a stack pointer when intending to expand memory to hold a larger buffer

Słabość nadrzędna

• CWE-762 Mismatched Memory Management Routines

Może prowadzić do

• CWE-123 Write-what-where Condition

Kiedy powstaje

• Implementation

Dotyczy

Memory-Unsafe, C

Uwagi

In C++, if the new operator was used to allocate the memory, it may be allocated with the malloc(), calloc() or realloc() family of functions in the implementation. Someone aware of this behavior might choose to map this problem to CWE-590 or to its parent, CWE-762, depending on their perspective.

Źródła

1. Valgrind
2. AddressSanitizer