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CWE-838 詳細

CWE-838

Inappropriate Encoding for Output Context
2011-03-30
00h00 +00:00
Incomplete
2026-10-28
00h00 +00:00
CWE Mitre.org
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名前: Inappropriate Encoding for Output Context

The product uses or specifies an encoding when generating output to a downstream component, but the specified encoding is not the same as the encoding that is expected by the downstream component.

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

クラス： Not Language-Specific (Undetermined)

一般的な結果

スコープ 影響 可能性
Integrity
Confidentiality
Availability		Modify Application Data, Execute Unauthorized Code or Commands

注記：An attacker could modify the structure of the message or data being sent to the downstream component. When the wrong encoding is used - even if closely related - the downstream component could decode the data incorrectly and misinterpret the output. This can have security consequences when the provided boundaries between control and data are inadvertently broken, because the resulting data could introduce control characters or special elements that were not sent by the product. The resulting data could then be used to bypass protection mechanisms such as input validation, and enable injection attacks.

観察された例

参考文献 説明

CVE-2009-2814

Server does not properly handle requests that do not contain UTF-8 data; browser assumes UTF-8, allowing XSS.

潜在的な緩和策

Phases : Implementation
Use context-aware encoding. That is, understand which encoding is being used by the downstream component, and ensure that this encoding is used. If an encoding can be specified, do so, instead of assuming that the default encoding is the same as the default being assumed by the downstream component.
Phases : Architecture and Design
Where possible, use communications protocols or data formats that provide strict boundaries between control and data. If this is not feasible, ensure that the protocols or formats allow the communicating components to explicitly state which encoding/decoding method is being used. Some template frameworks provide built-in support.
Phases : Architecture and Design

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 Base 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-468 Generic Cross-Browser Cross-Domain Theft
An attacker makes use of Cascading Style Sheets (CSS) injection to steal data cross domain from the victim's browser. The attack works by abusing the standards relating to loading of CSS: 1. Send cookies on any load of CSS (including cross-domain) 2. When parsing returned CSS ignore all data that does not make sense before a valid CSS descriptor is found by the CSS parser.

参考文献

REF-786

Injection-safe templating languages
Jim Manico.
https://manicode.blogspot.com/2010/06/injection-safe-templating-languages_30.html

REF-787

Can we please stop saying that XSS is boring and easy to fix!
Dinis Cruz.
http://diniscruz.blogspot.com/2010/09/can-we-please-stop-saying-that-xss-is.html

REF-788

Canoe: XSS prevention via context-aware output encoding
Ivan Ristic.
https://blog.ivanristic.com/2010/09/introducing-canoe-context-aware-output-encoding-for-xss-prevention.html

REF-789

What is the Future of Automated XSS Defense Tools?
Jim Manico.
http://software-security.sans.org/downloads/appsec-2011-files/manico-appsec-future-tools.pdf

REF-709

XSS Attacks
Jeremiah Grossman, Robert "RSnake" Hansen, Petko "pdp" D. Petkov, Anton Rager, Seth Fogie.

REF-725

DOM based XSS Prevention Cheat Sheet
OWASP.
http://www.owasp.org/index.php/DOM_based_XSS_Prevention_Cheat_Sheet

REF-45

OWASP Enterprise Security API (ESAPI) Project
OWASP.
https://owasp.org/www-project-enterprise-security-api/

登録情報

名前 組織 日付 リリース日 Version
CWE Content Team MITRE 2011-03-24 +00:00 2011-03-30 +00:00 1.12

変更履歴

名前 組織 日付 コメント
CWE Content Team MITRE 2011-06-01 +00:00 updated Common_Consequences, Relationships, Taxonomy_Mappings
CWE Content Team MITRE 2011-06-27 +00:00 updated Demonstrative_Examples, Related_Attack_Patterns, Relationships
CWE Content Team MITRE 2012-05-11 +00:00 updated Potential_Mitigations, References, Relationships, Taxonomy_Mappings
CWE Content Team MITRE 2017-11-08 +00:00 updated References, Taxonomy_Mappings
CWE Content Team MITRE 2019-01-03 +00:00 updated Relationships, Taxonomy_Mappings
CWE Content Team MITRE 2019-06-20 +00:00 updated Relationships
CWE Content Team MITRE 2020-02-24 +00:00 updated Relationships
CWE Content Team MITRE 2023-01-31 +00:00 updated Description
CWE Content Team MITRE 2023-04-27 +00:00 updated Detection_Factors, References, Relationships
CWE Content Team MITRE 2023-06-29 +00:00 updated Mapping_Notes
CWE Content Team MITRE 2025-09-09 +00:00 updated References
CWE Content Team MITRE 2025-12-11 +00:00 updated Time_of_Introduction, Weakness_Ordinalities
CWE Content Team MITRE 2026-10-28 +00:00 updated Common_Consequences, Description
CVE Findに掲載されている情報は、慎重に選定された複数の参照ソースから取得されています。CVEデータはMITRE Corporationおよび国家脆弱性データベース（NVD）が提供しています。既知の悪用された脆弱性（KEV）カタログはサイバーセキュリティ・インフラセキュリティ庁（CISA）から、EPSSスコアはFIRST.orgから取得しています。また、ソフトウェアの弱点（CWE）および共通攻撃パターン（CAPEC）に関するデータはMITRE Corporationが管理し、ハードウェアおよびソフトウェア構成（CPE）に関する情報はNVDが提供しています。