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CWE-470

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CWE-470

Use of Externally-Controlled Input to Select Classes or Code ('Unsafe Reflection')

Base
Draft

Description

The product uses external input with reflection to select which classes or code to use, but it does not sufficiently prevent the input from selecting improper classes or code.

If the product uses external inputs to determine which class to instantiate or which method to invoke, then an attacker could supply values to select unexpected classes or methods. If this occurs, then the attacker could create control flow paths that were not intended by the developer. These paths could bypass authentication or access control checks, or otherwise cause the product to behave in an unexpected manner. This situation becomes a doomsday scenario if the attacker can upload files into a location that appears on the product's classpath (CWE-427) or add new entries to the product's classpath (CWE-426). Under either of these conditions, the attacker can use reflection to introduce new, malicious behavior into the product.

Common Consequences

Scope

Integrity
Confidentiality
Availability
Other

Impact

Execute Unauthorized Code or Commands, Alter Execution Logic

Scope

Availability
Other

Impact

DoS: Crash, Exit, or Restart, Other

Scope

Confidentiality

Impact

Read Application Data

Potential Mitigations

Architecture and Design

Refactor your code to avoid using reflection.

Architecture and Design

Do not use user-controlled inputs to select and load classes or code.

Implementation

Apply strict input validation by using allowlists or indirect selection to ensure that the user is only selecting allowable classes or code.

CVE-2018-1000613

Cryptography API uses unsafe reflection when deserializing a private key

CVE-2004-2331

Database system allows attackers to bypass sandbox restrictions by using the Reflection API.

Applicable Platforms

Java
PHP
Interpreted

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