이름: Improper Neutralization of Special Elements used in an Expression Language Statement

The product constructs all or part of an expression language (EL) statement in a framework such as a Java Server Page (JSP) using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended EL statement before it is executed.

일반 정보

배경 세부 정보

취약점 도입 방식

Architecture and Design
Implementation

적용 가능한 플랫폼

언어

이름: Java (Undetermined)

일반적인 결과

범위	영향	가능성
Confidentiality	Read Application Data 참고: An attacker could insert an expression that references private data, which is then included in the output.
Integrity	Execute Unauthorized Code or Commands 참고: An attacker could execute arbitrary expressions.

관찰된 예시

참고 자료	설명
CVE-2021-44228	Product does not neutralize ${xyz} style expressions, allowing remote code execution. (log4shell vulnerability in log4j)

잠재적 완화 방법

Phases : Architecture and Design
Avoid adding user-controlled data into an expression interpreter when possible.
Phases : Implementation
Phases : System Configuration // Operation
The framework or tooling might allow the developer to disable or deactivate the processing of EL expressions, such as setting the isELIgnored attribute for a JSP page to "true".

탐지 방법

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.)
효과성 : High

취약점 매핑 메모

근거 : 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.
댓글 : 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.

메모

The interrelationships and differences between CWE-917 and CWE-1336 need to be further clarified.
In certain versions of Spring 3.0.5 and earlier, there was a vulnerability (CVE-2011-2730) in which Expression Language tags would be evaluated twice, which effectively exposed any application to EL injection. However, even for later versions, this weakness is still possible depending on configuration.

참고 자료

REF-1534

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

제출

이름	조직	날짜	출시일	Version
CWE Content Team	MITRE	2013-02-15 +00:00	2013-02-21 +00:00	2.4

수정 사항

이름	조직	날짜	댓글
CWE Content Team	MITRE	2017-11-08 +00:00	updated References
CWE Content Team	MITRE	2018-03-27 +00:00	updated Relationships
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	2021-07-20 +00:00	updated References
CWE Content Team	MITRE	2021-10-28 +00:00	updated Relationships
CWE Content Team	MITRE	2022-06-28 +00:00	updated Description, Maintenance_Notes, Observed_Examples, Potential_Mitigations, References, 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	2025-12-11 +00:00	updated Relationships
CWE Content Team	MITRE	2026-10-28 +00:00	updated Alternate_Terms, Background_Details, Common_Consequences, Description, Name, References

CWE-917 상세 정보

CWE-917