Access of Memory Location Before Start of BufferID: 786 | Date: (C)2012-05-14 (M)2022-10-10 |
Type: weakness | Status: INCOMPLETE |
Abstraction Type: Base |
Description
The software reads or writes to a buffer using an index or
pointer that references a memory location prior to the beginning of the buffer.
Extended DescriptionThis 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.
Applicable PlatformsNone
Common Consequences
Scope | Technical Impact | Notes |
---|
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 buffers position in memory, this knowledge can be used to
craft further attacks, possibly with more severe consequences. |
IntegrityAvailability | Modify memoryDoS: crash / exit /
restart | Out of bounds memory access will very likely result in the corruption
of relevant memory, and perhaps instructions, possibly leading to a
crash. |
| Modify memoryExecute 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. |
Detection MethodsNone
Potential MitigationsNone
Relationships
Related CWE | Type | View | Chain |
---|
CWE-786 ChildOf CWE-119 | Weakness | CWE-1000CWE-699 | |
Demonstrative Examples (Details)
- In the following C/C++ example, a utility function is used to trim
trailing whitespace from a character string. The function copies the input
string to a local character string and uses a while statement to remove the
trailing whitespace by moving backward through the string and overwriting
whitespace with a NUL character. (Demonstrative Example Id DX-87)
- The following example asks a user for an offset into an array to
select an item. (Demonstrative Example Id DX-90)
- The following is an example of code that may result in a buffer
underwrite, if find() returns a negative value to indicate that ch is not
found in srcBuf: (Demonstrative Example Id DX-88)
Observed Examples
- 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
For more examples, refer to CVE relations in the bottom box.
White Box Definitions None
Black Box Definitions None
Taxynomy MappingsNone
References:None