VariantIncompleteCWE-590

CWE-590: Free of Memory not on the Heap

Description

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.

Abstraction: VariantA weakness tied to a specific language, technology or resource.
Likelihood of exploit: Not rated by MITRE
Status: Incomplete

Common consequences

IntegrityConfidentialityAvailability
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.

Potential mitigations

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 DesignLibraries 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.

Related weaknesses

Parent weaknesses

CWE-762Mismatched Memory Management Routines

Can lead to

CWE-123Write-what-where Condition

CAPEC attack patterns that exploit it

CWE 4.20 links no CAPEC attack pattern to this weakness.

Description

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

Common consequences

IntegrityConfidentialityAvailability

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.

Potential mitigations

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 DesignLibraries 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.