COMMON WEAKNESS ENUMERATIONIncomplete

CWE-543

Use of Singleton Pattern Without Synchronization in a Multithreaded Context

The product uses the singleton pattern when creating a resource within a multithreaded environment.

Abstraction

Variant

Structure

Simple

Likelihood of Exploit

Medium

Understand the problem

What is the problem?

The product uses the singleton pattern when creating a resource within a multithreaded environment.

Extended description

The use of a singleton pattern may not be thread-safe.

Root cause

How and when does the problem arise?

Lifecycle phase

Implementation

Risk

What does successful exploitation lead to?

OtherModify Application Data

Affected security scopes: Other, Integrity

Defence

How is it prevented and fixed?

Architecture and Design

Architecture and design approach

Detail
Use the Thread-Specific Storage Pattern. See References.

Implementation

Implementation-phase defence

Detail
Do not use member fields to store information in the Servlet. In multithreading environments, storing user data in Servlet member fields introduces a data access race condition.

Implementation

Implementation-phase defence

Detail
Avoid using the double-checked locking pattern in language versions that cannot guarantee thread safety. This pattern may be used to avoid the overhead of a synchronized call, but in certain versions of Java (for example), this has been shown to be unsafe because it still introduces a race condition (CWE-209).

Effectiveness: Limited

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.)