CWE-825Expired Pointer Dereference

Description

The product dereferences a pointer that contains a location for memory that was previously valid, but is no longer valid.

When a product releases memory, but it maintains a pointer to that memory, then the memory might be re-allocated at a later time. If the original pointer is accessed to read or write data, then this could cause the product to read or modify data that is in use by a different function or process. Depending on how the newly-allocated memory is used, this could lead to a denial of service, information exposure, or code execution.

Common consequences

• Confidentiality→Read Memory
  If the expired pointer is used in a read operation, an attacker might be able to control data read in by the application.
• Availability→DoS: Crash, Exit, or Restart
  If the expired pointer references a memory location that is not accessible to the product, or points to a location that is "malformed" (such as NULL) or larger than expected by a read or write operation, then a crash may occur.
• Integrity,Confidentiality,Availability→Execute Unauthorized Code or Commands
  If the expired pointer is used in a function call, or points to unexpected data in a write operation, then code execution may be possible.

Potential mitigations

• 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.

Related CWEs

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