Incorrect Pointer Scaling

Opis

In C and C++, one may often accidentally refer to the wrong memory due to the semantics of when math operations are implicitly scaled.

Skutki

• Confidentiality, Integrity

  Read Memory; Modify Memory

  Incorrect pointer scaling will often result in buffer overflow conditions. Confidentiality can be compromised if the weakness is in the context of a buffer over-read or under-read.

Zapobieganie

• Architecture and Design

  Use a platform with high-level memory abstractions.

• Implementation

  Always use array indexing instead of direct pointer manipulation.

• Architecture and Design

  Use technologies for preventing buffer overflows.

Słabość nadrzędna

• CWE-682 Incorrect Calculation

Kiedy powstaje

• Implementation — Programmers may try to index from a pointer by adding a number of bytes. This is incorrect because C and C++ implicitly scale the operand by the size of the data type.

Dotyczy

C, C++

Źródła

1. The CLASP Application Security Process — Secure Software, Inc., 2005
2. The Art of Software Security Assessment — Mark Dowd, John McDonald, Justin Schuh, Chapter 6, "Pointer Arithmetic", Page 277, Addison Wesley, 2006