CWE-786—Access of Memory Location Before Start of Buffer

Weakness Name

Access of Memory Location Before Start of Buffer

Description

The product reads or writes to a buffer using an index or pointer that references a memory location prior to the beginning of the buffer.

This typically occurs when a pointer or its index is decremented to a position before the buffer, when pointer arithmetic results in a position before the beginning of the valid memory location, or when a negative index is used.

Common Consequences

Scope:

Confidentiality

Impact:

Read Memory

Notes:

For an out-of-bounds read, the attacker may have access to sensitive information. If the sensitive information contains system details, such as the current buffer's position in memory, this knowledge can be used to craft further attacks, possibly with more severe consequences.

Scope:

Integrity, Availability

Impact:

Modify Memory, DoS: Crash, Exit, or Restart

Notes:

Out of bounds memory access will very likely result in the corruption of relevant memory, and perhaps instructions, possibly leading to a crash.

Scope:

Integrity

Impact:

Modify Memory, Execute Unauthorized Code or Commands

Notes:

If the corrupted memory can be effectively controlled, it may be possible to execute arbitrary code. If the corrupted memory is data rather than instructions, the system will continue to function with improper changes, possibly in violation of an implicit or explicit policy.

Related Weaknesses

• CWE-119Improper Restriction of Operations within the Bounds of a Memory BufferHigh