Chi tiết CWE-170

The product does not terminate or incorrectly terminates a string or array with a null character or equivalent terminator.

Các cách xuất hiện

Implementation : Null termination errors frequently occur in two different ways. An off-by-one error could cause a null to be written out of bounds, leading to an overflow. Or, a program could use a strncpy() function call incorrectly, which prevents a null terminator from being added at all. Other scenarios are possible.

Nền tảng áp dụng

Ngôn ngữ

Tên: C (Undetermined)
Tên: C++ (Undetermined)

Hậu quả phổ biến

Ví dụ đã quan sát

Các biện pháp giảm thiểu tiềm năng

Phases : Requirements
Use a language that is not susceptible to these issues. However, be careful of null byte interaction errors (CWE-626) with lower-level constructs that may be written in a language that is susceptible.
Phases : Implementation
Ensure that all string functions used are understood fully as to how they append null characters. Also, be wary of off-by-one errors when appending nulls to the end of strings.
Phases : Implementation
If performance constraints permit, special code can be added that validates null-termination of string buffers, this is a rather naive and error-prone solution.
Phases : Implementation
Switch to bounded string manipulation functions. Inspect buffer lengths involved in the buffer overrun trace reported with the defect.
Phases : Implementation
Add code that fills buffers with nulls (however, the length of buffers still needs to be inspected, to ensure that the non null-terminated string is not written at the physical end of the buffer).

Phương pháp phát hiện

Automated Static Analysis

Automated static analysis, commonly referred to as Static Application Security Testing (SAST), can find some instances of this weakness by analyzing source code (or binary/compiled code) without having to execute it. Typically, this is done by building a model of data flow and control flow, then searching for potentially-vulnerable patterns that connect "sources" (origins of input) with "sinks" (destinations where the data interacts with external components, a lower layer such as the OS, etc.)
Hiệu quả : High

Ghi chú ánh xạ lỗ hổng

Lý do : This CWE entry is at the Base level of abstraction, which is a preferred level of abstraction for mapping to the root causes of vulnerabilities.
Bình luận : Carefully read both the name and description to ensure that this mapping is an appropriate fit. Do not try to 'force' a mapping to a lower-level Base/Variant simply to comply with this preferred level of abstraction.

Ghi chú

Factors: this is usually resultant from other weaknesses such as off-by-one errors, but it can be primary to boundary condition violations such as buffer overflows. In buffer overflows, it can act as an expander for assumed-immutable data.
Overlaps missing input terminator.

As currently described, this entry is more like a category than a weakness.

Tài liệu tham khảo

REF-1534

Automated Technical Debt Measure, Version 2
OMG.
https://www.omg.org/spec/ATDM2/1.0/PDF

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