Tên: Unsigned to Signed Conversion Error

The product uses an unsigned primitive and performs a cast to a signed primitive, which can produce an unexpected value if the value of the unsigned primitive can not be represented using a signed primitive.

Thông tin chung

Các cách xuất hiện

Implementation

Nền tảng áp dụng

Ngôn ngữ

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

Hậu quả phổ biến

Phạm vi	Tác động	Khả năng xảy ra
Availability	DoS: Crash, Exit, or Restart Ghi chú: Incorrect sign conversions generally lead to undefined behavior, and therefore crashes.
Integrity	Modify Memory Ghi chú: If a poor cast leads to a buffer overflow or similar condition, data integrity may be affected. This can be a precursor to dangerous buffer underwrite conditions that allow attackers to move down the stack where they otherwise might not have access in a normal buffer overflow condition. Buffer underwrites occur frequently when large unsigned values are cast to signed values, and then used as indexes into a buffer or for pointer arithmetic.
Integrity Confidentiality Availability Access Control	Execute Unauthorized Code or Commands, Bypass Protection Mechanism Ghi chú: Improper signed-to-unsigned conversions without proper checking can sometimes trigger buffer overflows which can be used to execute arbitrary code. This is usually outside the scope of a program's implicit security policy.

Các biện pháp giảm thiểu tiềm năng

Phases : Requirements
Choose a language which is not subject to these casting flaws.
Phases : Architecture and Design
Design object accessor functions to implicitly check values for valid sizes. Ensure that all functions which will be used as a size are checked previous to use as a size. If the language permits, throw exceptions rather than using in-band errors.
Phases : Implementation
Error check the return values of all functions. Be aware of implicit casts made, and use unsigned variables for sizes if at all possible.

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 Variant 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.

Mẫu tấn công liên quan

ID CAPEC	Tên mẫu tấn công
CAPEC-92	Forced Integer Overflow This attack forces an integer variable to go out of range. The integer variable is often used as an offset such as size of memory allocation or similarly. The attacker would typically control the value of such variable and try to get it out of range. For instance the integer in question is incremented past the maximum possible value, it may wrap to become a very small, or negative number, therefore providing a very incorrect value which can lead to unexpected behavior. At worst the attacker can execute arbitrary code.

Tài liệu tham khảo

REF-62

The Art of Software Security Assessment
Mark Dowd, John McDonald, Justin Schuh.

REF-18

The CLASP Application Security Process
Secure Software, Inc..
https://cwe.mitre.org/documents/sources/TheCLASPApplicationSecurityProcess.pdf

REF-1534

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

Gửi

Tên	Tổ chức	Ngày	Ngày phát hành	Version
CLASP		2006-07-19 +00:00	2006-07-19 +00:00	Draft 3

Sửa đổi

Tên	Tổ chức	Ngày	Bình luận
CWE Content Team	MITRE	2008-09-08 +00:00	updated Applicable_Platforms, Common_Consequences, Relationships, Other_Notes, Taxonomy_Mappings
CWE Content Team	MITRE	2009-05-27 +00:00	updated Demonstrative_Examples
CWE Content Team	MITRE	2009-10-29 +00:00	updated Common_Consequences
CWE Content Team	MITRE	2010-12-13 +00:00	updated Other_Notes
CWE Content Team	MITRE	2011-06-01 +00:00	updated Common_Consequences
CWE Content Team	MITRE	2012-05-11 +00:00	updated References, Relationships
CWE Content Team	MITRE	2012-10-30 +00:00	updated Potential_Mitigations
CWE Content Team	MITRE	2014-06-23 +00:00	updated Demonstrative_Examples, Description, Other_Notes
CWE Content Team	MITRE	2014-07-30 +00:00	updated Relationships, Taxonomy_Mappings
CWE Content Team	MITRE	2020-02-24 +00:00	updated Relationships
CWE Content Team	MITRE	2020-08-20 +00:00	updated Relationships
CWE Content Team	MITRE	2020-12-10 +00:00	updated Relationships
CWE Content Team	MITRE	2021-03-15 +00:00	updated References
CWE Content Team	MITRE	2023-01-31 +00:00	updated Description
CWE Content Team	MITRE	2023-04-27 +00:00	updated Relationships
CWE Content Team	MITRE	2023-06-29 +00:00	updated Mapping_Notes
CWE Content Team	MITRE	2025-12-11 +00:00	updated Detection_Factors, Weakness_Ordinalities
CWE Content Team	MITRE	2026-10-28 +00:00	updated Common_Consequences, Description, References, Relationships

Chi tiết CWE-196

CWE-196