CWE-416Use After Free

Description

Common consequences· 4

• Integrity — Modify Memory
  The use of previously freed memory may corrupt valid data, if the memory area in question has been allocated and used properly elsewhere.
• Availability — DoS: Crash, Exit, or Restart
  If chunk consolidation occurs after the use of previously freed data, the process may crash when invalid data is used as chunk information.
• Confidentiality — Read Memory
  Read operations on freed memory can sometimes leak sensitive information instead of causing a crash
• Integrity / Confidentiality / Availability — Execute Unauthorized Code or Commands
  If malicious data is entered before chunk consolidation can take place, it may be possible to take advantage of a write-what-where primitive to execute arbitrary code. If the newly allocated data happens to hold a class, in C++ for example, various function pointers may be scattered within the heap data. If one of these function pointers is overwritten with an address to valid shellcode, execution of arbitrary code can be achieved.

Potential mitigations· 2

• [Architecture and Design]Choose a language that provides automatic memory management.
• [Implementation]When freeing pointers, be sure to set them to NULL once they are freed. However, the utilization of multiple or complex data structures may lower the usefulness of this strategy.

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Related by meaning· 6

Nearest entities by semantic similarity across the cs-graph corpus.