CWE-196
Unsigned to Signed Conversion Error
2006-07-19
00h00 +00:00
00h00 +00:00
特定のCWEの通知
特定のCWEの変更情報をいち早くお届けします。
名前: 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.
一般情報
導入モード
Implementation適用可能なプラットフォーム
言語
名前： C (Undetermined)名前： C++ (Undetermined)
一般的な結果
| スコープ | 影響 | 可能性 |
|---|---|---|
| Availability | DoS: Crash, Exit, or Restart 注記：Incorrect sign conversions generally lead to undefined behavior, and therefore crashes. | |
| Integrity | Modify Memory 注記：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 注記：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. |
潜在的な緩和策
Phases : RequirementsChoose 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.
検出方法
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.)有効性 : High
脆弱性マッピングノート
理由 : 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.コメント : 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.
関連する攻撃パターン
| CAPEC ID | 攻撃パターン名 |
|---|---|
| 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. |
参考文献
REF-62
The Art of Software Security AssessmentMark Dowd, John McDonald, Justin Schuh.
REF-18
The CLASP Application Security ProcessSecure Software, Inc..
https://cwe.mitre.org/documents/sources/TheCLASPApplicationSecurityProcess.pdf
REF-1534
Automated Technical Debt Measure, Version 2OMG.
https://www.omg.org/spec/ATDM2/1.0/PDF
登録情報
| 名前 | 組織 | 日付 | リリース日 | Version |
|---|---|---|---|---|
| CLASP | Draft 3 |
変更履歴
| 名前 | 組織 | 日付 | コメント |
|---|---|---|---|
| CWE Content Team | MITRE | updated Applicable_Platforms, Common_Consequences, Relationships, Other_Notes, Taxonomy_Mappings | |
| CWE Content Team | MITRE | updated Demonstrative_Examples | |
| CWE Content Team | MITRE | updated Common_Consequences | |
| CWE Content Team | MITRE | updated Other_Notes | |
| CWE Content Team | MITRE | updated Common_Consequences | |
| CWE Content Team | MITRE | updated References, Relationships | |
| CWE Content Team | MITRE | updated Potential_Mitigations | |
| CWE Content Team | MITRE | updated Demonstrative_Examples, Description, Other_Notes | |
| CWE Content Team | MITRE | updated Relationships, Taxonomy_Mappings | |
| CWE Content Team | MITRE | updated Relationships | |
| CWE Content Team | MITRE | updated Relationships | |
| CWE Content Team | MITRE | updated Relationships | |
| CWE Content Team | MITRE | updated References | |
| CWE Content Team | MITRE | updated Description | |
| CWE Content Team | MITRE | updated Relationships | |
| CWE Content Team | MITRE | updated Mapping_Notes | |
| CWE Content Team | MITRE | updated Detection_Factors, Weakness_Ordinalities | |
| CWE Content Team | MITRE | updated Common_Consequences, Description, References, Relationships |
