Serializable Class Containing Sensitive Data

Draft Variant

Structure: Simple

Description

The code contains a class with sensitive data, but the class does not explicitly deny serialization. The data can be accessed by serializing the class through another class.

Extended Description

Serializable classes are effectively open classes since data cannot be hidden in them. Classes that do not explicitly deny serialization can be serialized by any other class, which can then in turn use the data stored inside it.

Common Consequences 1

Scope: Confidentiality

Impact: Read Application Data

an attacker can write out the class to a byte stream, then extract the important data from it.

Detection Methods 1

Automated Static AnalysisHigh

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.)

Potential Mitigations 2

Phase: Implementation

In Java, explicitly define final writeObject() to prevent serialization. This is the recommended solution. Define the writeObject() function to throw an exception explicitly denying serialization.

Phase: Implementation

Make sure to prevent serialization of your objects.

Demonstrative Examples 1

This code creates a new record for a medical patient:

Code Example:Bad
Java
java

This object does not explicitly deny serialization, allowing an attacker to serialize an instance of this object and gain a patient's name and Social Security number even though those fields are private.

References 1

The CLASP Application Security Process

Secure Software, Inc.

2005

https://cwe.mitre.org/documents/sources/TheCLASPApplicationSecurityProcess.pdf(2024-11-17)

ID: REF-18

Likelihood of Exploit

High

Applicable Platforms

Languages:

Java : Undetermined

Modes of Introduction

Implementation

Related Weaknesses

ChildOf:

Exposure of Resource to Wrong Sphere (CWE-668)

CanPrecede:

Exposure of Sensitive Information to an Unauthorized Actor (CWE-200)

Taxonomy Mapping

CLASP
The CERT Oracle Secure Coding Standard for Java (2011)
The CERT Oracle Secure Coding Standard for Java (2011)
Software Fault Patterns