CWE-1321
Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution')
AI Translation Available
The product receives input from an upstream component that specifies attributes that are to be initialized or updated in an object, but it does not properly control modifications of attributes of the object prototype.
Status
incomplete
Abstraction
variant
Affected Platforms
JavaScript
Technical Details
AI Translation
Common Consequences
confidentiality
integrity
availability
Impacts
read application data
modify application data
dos: crash, exit, or restart
Detection Methods
automated static analysis
Potential Mitigations
Phases:
implementation
architecture and design
Descriptions:
•
By blocking modifications of attributes that resolve to object prototype, such as proto or prototype, this weakness can be mitigated.
•
By using an object without prototypes (via Object.create(null) ), adding object prototype attributes by accessing the prototype via the special attributes becomes impossible, mitigating this weakness.
•
By freezing the object prototype first (for example, Object.freeze(Object.prototype)), modification of the prototype becomes impossible.
•
When handling untrusted objects, validating using a schema can be used.
•
Map can be used instead of objects in most cases. If Map methods are used instead of object attributes, it is not possible to access the object prototype or modify it.