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Weakness · High

CWE-763: Release of Invalid Pointer or Reference

What it is

The product attempts to return a memory resource to the system, but it calls the wrong release function or calls the appropriate release function incorrectly.

MITRE CWE 4.19.1

Severity (our rating)
High
Likelihood of exploit
Not rated by MITRE
Introduced during
Implementation
Exploited in the wild
No CVE in CISA's catalog

In more detail

This weakness can take several forms, such as: The memory was allocated, explicitly or implicitly, via one memory management method and deallocated using a different, non-compatible function (CWE-762). The function calls or memory management routines chosen are appropriate, however they are used incorrectly, such as in CWE-761.

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().
  • When programming in C++, consider using smart pointers provided by the boost library to help correctly and consistently manage memory.

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.

Testing

  • Use a tool that dynamically detects memory management problems, such as valgrind.

How to find it

  • 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.
  • 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++.

CWE-763 on MITRE's CWE site

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Source: MITRE Common Weakness Enumeration, CWE version 4.19.1. CWE is a trademark of The MITRE Corporation.