Access of Memory Location Before Start of Buffer

Opis

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.

Skutki

• Confidentiality

  Read Memory

  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.

• Integrity, Availability

  Modify Memory; DoS: Crash, Exit, or Restart

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

• Integrity

  Modify Memory; Execute Unauthorized Code or Commands

  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.

Przykłady podatności

• CVE-2002-2227 Unchecked length of SSLv2 challenge value leads to buffer underflow.
• CVE-2007-4580 Buffer underflow from a small size value with a large buffer (length parameter inconsistency, CWE-130)
• CVE-2007-1584 Buffer underflow from an all-whitespace string, which causes a counter to be decremented before the buffer while looking for a non-whitespace character.
• CVE-2007-0886 Buffer underflow resultant from encoded data that triggers an integer overflow.
• CVE-2006-6171 Product sets an incorrect buffer size limit, leading to "off-by-two" buffer underflow.
• CVE-2006-4024 Negative value is used in a memcpy() operation, leading to buffer underflow.
• CVE-2004-2620 Buffer underflow due to mishandled special characters

Słabość nadrzędna

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

Słabości podrzędne

• CWE-124 Buffer Underwrite ('Buffer Underflow')
• CWE-127 Buffer Under-read

Kiedy powstaje

• Implementation

Dotyczy

Memory-Unsafe, C, C++

Źródła

1. AddressSanitizer