COMMON WEAKNESS ENUMERATIONDraft

CWE-498

Cloneable Class Containing Sensitive Information

The code contains a class with sensitive data, but the class is cloneable. The data can then be accessed by cloning the class.

Abstraction

Variant

Structure

Simple

Likelihood of Exploit

Medium

Understand the problem

What is the problem?

The code contains a class with sensitive data, but the class is cloneable. The data can then be accessed by cloning the class.

Extended description

Cloneable classes are effectively open classes, since data cannot be hidden in them. Classes that do not explicitly deny cloning can be cloned by any other class without running the constructor.

Root cause

How and when does the problem arise?

Lifecycle phase

Implementation

Risk

What does successful exploitation lead to?

Bypass Protection Mechanism

Affected security scopes: Access Control

A class that can be cloned can be produced without executing the constructor. This is dangerous since the constructor may perform security-related checks. By allowing the object to be cloned, those checks may be bypassed.

Defence

How is it prevented and fixed?

Implementation

Implementation-phase defence

Detail
If you do make your classes clonable, ensure that your clone method is final and throw super.clone().

Verification

How is it detected?

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.)