CWE-590: Free of Memory not on the Heap
CWE版本: 4.18
更新日期: 2025-09-09
弱点描述
The product calls free() on a pointer to memory that was not allocated using associated heap allocation functions such as malloc(), calloc(), or realloc().
扩展描述
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.
常见后果
影响范围: Integrity Confidentiality Availability
技术影响: Execute Unauthorized Code or Commands Modify Memory
说明: 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.
潜在缓解措施
阶段: Implementation
描述: 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.
阶段: Implementation
描述: 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.
阶段: Architecture and Design
策略: Libraries or Frameworks
阶段: Architecture and Design
描述: Use a language that provides abstractions for memory allocation and deallocation.
阶段: Testing
描述: Use a tool that dynamically detects memory management problems, such as valgrind.
检测方法
方法: Fuzzing
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.
有效性: High
方法: Automated Static Analysis
Automated static analysis, commonly referred to as Static Application Security Testing (SAST), can find some instances of this weakness by analyzing source code (or binary/compiled code) without having to execute it. Typically, this is done by building a model of data flow and control flow, then searching for potentially-vulnerable patterns that connect "sources" (origins of input) with "sinks" (destinations where the data interacts with external components, a lower layer such as the OS, etc.)
有效性: High
引入模式
| 阶段 | 说明 |
|---|---|
| Implementation | - |
分类映射
| 分类名称 | 条目ID | 条目名称 | 映射适配度 |
|---|---|---|---|
| CERT C Secure Coding | MEM34-C | Only free memory allocated dynamically | Exact |
| CERT C Secure Coding | WIN30-C | Properly pair allocation and deallocation functions | Imprecise |
| Software Fault Patterns | SFP12 | Faulty Memory Release | - |