Semantics and Security Issues in JavaScript

TL;DR

This paper provides an accessible overview of JavaScript semantics focused on security issues, highlighting language features that can lead to vulnerabilities and offering coding best practices and ECMAScript 5 updates.

Contribution

It offers a digest of JavaScript semantics emphasizing security concerns, making complex formal semantics accessible and practical for developers.

Findings

Identifies semantic features leading to security vulnerabilities

Provides coding patterns to mitigate common traps

Highlights ECMAScript 5 features enhancing security

Abstract

There is a plethora of research articles describing the deep semantics of JavaScript. Nevertheless, such articles are often difficult to grasp for readers not familiar with formal semantics. In this report, we propose a digest of the semantics of JavaScript centered around security concerns. This document proposes an overview of the JavaScript language and the misleading semantic points in its design. The first part of the document describes the main characteristics of the language itself. The second part presents how those characteristics can lead to problems. It finishes by showing some coding patterns to avoid certain traps and presents some ECMAScript 5 new features.