CWE-470 Detail

CWE-470

Use of Externally-Controlled Input to Select Classes or Code ('Unsafe Reflection')
Draft
2006-07-19
00h00 +00:00
2023-10-26
00h00 +00:00
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Name: Use of Externally-Controlled Input to Select Classes or Code ('Unsafe Reflection')

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.

CWE Description

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.

General Informations

Modes Of Introduction

Architecture and Design
Implementation

Applicable Platforms

Language

Name: Java (Undetermined)
Name: PHP (Undetermined)
Class: Interpreted (Sometimes)

Common Consequences

Scope Impact Likelihood
Integrity
Confidentiality
Availability
Other		Execute Unauthorized Code or Commands, Alter Execution Logic

Note: The attacker might be able to execute code that is not directly accessible to the attacker. Alternately, the attacker could call unexpected code in the wrong place or the wrong time, possibly modifying critical system state.
Availability
Other		DoS: Crash, Exit, or Restart, Other

Note: The attacker might be able to use reflection to call the wrong code, possibly with unexpected arguments that violate the API (CWE-227). This could cause the product to exit or hang.
ConfidentialityRead Application Data

Note: By causing the wrong code to be invoked, the attacker might be able to trigger a runtime error that leaks sensitive information in the error message, such as CWE-536.

Observed Examples

References Description

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.

Potential Mitigations

Phases : Architecture and Design
Refactor your code to avoid using reflection.
Phases : Architecture and Design
Do not use user-controlled inputs to select and load classes or code.
Phases : Implementation
Apply strict input validation by using allowlists or indirect selection to ensure that the user is only selecting allowable classes or code.

Detection Methods

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.)
Effectiveness : High

Vulnerability Mapping Notes

Justification : 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.
Comment : 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.

Related Attack Patterns

CAPEC-ID Attack Pattern Name
CAPEC-138 Reflection Injection
An adversary supplies a value to the target application which is then used by reflection methods to identify a class, method, or field. For example, in the Java programming language the reflection libraries permit an application to inspect, load, and invoke classes and their components by name. If an adversary can control the input into these methods including the name of the class/method/field or the parameters passed to methods, they can cause the targeted application to invoke incorrect methods, read random fields, or even to load and utilize malicious classes that the adversary created. This can lead to the application revealing sensitive information, returning incorrect results, or even having the adversary take control of the targeted application.

References

REF-6

Seven Pernicious Kingdoms: A Taxonomy of Software Security Errors
Katrina Tsipenyuk, Brian Chess, Gary McGraw.
https://samate.nist.gov/SSATTM_Content/papers/Seven%20Pernicious%20Kingdoms%20-%20Taxonomy%20of%20Sw%20Security%20Errors%20-%20Tsipenyuk%20-%20Chess%20-%20McGraw.pdf

Submission

Name Organization Date Date release Version
7 Pernicious Kingdoms 2006-07-19 +00:00 2006-07-19 +00:00 Draft 3

Modifications

Name Organization Date Comment
Eric Dalci Cigital 2008-07-01 +00:00 updated Potential_Mitigations, Time_of_Introduction
KDM Analytics 2008-08-01 +00:00 added/updated white box definitions
CWE Content Team MITRE 2008-09-08 +00:00 updated Description, Relationships, Other_Notes, Taxonomy_Mappings
CWE Content Team MITRE 2008-10-14 +00:00 updated Applicable_Platforms, Demonstrative_Examples, Description, Other_Notes
CWE Content Team MITRE 2009-01-12 +00:00 updated Applicable_Platforms, Common_Consequences, Demonstrative_Examples, Observed_Examples, Potential_Mitigations
CWE Content Team MITRE 2009-05-27 +00:00 updated Demonstrative_Examples, Name
CWE Content Team MITRE 2009-10-29 +00:00 updated Alternate_Terms, Relationships
CWE Content Team MITRE 2011-03-29 +00:00 updated Demonstrative_Examples
CWE Content Team MITRE 2011-06-01 +00:00 updated Common_Consequences, Relationships, Taxonomy_Mappings
CWE Content Team MITRE 2012-05-11 +00:00 updated Relationships, Taxonomy_Mappings
CWE Content Team MITRE 2013-02-21 +00:00 updated Relationships
CWE Content Team MITRE 2014-07-30 +00:00 updated Relationships
CWE Content Team MITRE 2017-11-08 +00:00 updated White_Box_Definitions
CWE Content Team MITRE 2019-01-03 +00:00 updated Taxonomy_Mappings
CWE Content Team MITRE 2019-06-20 +00:00 updated Relationships
CWE Content Team MITRE 2020-02-24 +00:00 updated References, Relationships
CWE Content Team MITRE 2020-06-25 +00:00 updated Potential_Mitigations
CWE Content Team MITRE 2021-10-28 +00:00 updated Relationships
CWE Content Team MITRE 2023-01-31 +00:00 updated Common_Consequences, Demonstrative_Examples, Description, Related_Attack_Patterns, Relationships
CWE Content Team MITRE 2023-04-27 +00:00 updated Detection_Factors, Relationships
CWE Content Team MITRE 2023-06-29 +00:00 updated Mapping_Notes
CWE Content Team MITRE 2023-10-26 +00:00 updated Observed_Examples