CWE-917
Improper Neutralization of Special Elements used in an Expression Language Statement ('Expression Language Injection')
AI Translation Available
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.
Status
incomplete
Abstraction
base
Affected Platforms
Java
Extended Description
AI Translation
Frameworks such as Java Server Page (JSP) allow a developer to insert executable expressions within otherwise-static content. When the developer is not aware of the executable nature of these expressions and/or does not disable them, then if an attacker can inject expressions, this could lead to code execution or other unexpected behaviors.
Technical Details
AI Translation
Common Consequences
confidentiality
integrity
Impacts
read application data
execute unauthorized code or commands
Detection Methods
automated static analysis
Potential Mitigations
Phases:
architecture and design
implementation
system configuration
operation
Descriptions:
•
Avoid adding user-controlled data into an expression interpreter when possible.
•
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".
•
If user-controlled data must be added to an expression interpreter, one or more of the following should be performed:
- Validate that the user input will not evaluate as an expression
- Encode the user input in a way that ensures it is not evaluated as an expression