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Client Fingerprinting via Analysis of Browser Scripting Environment


Beyond using the User Agent, there are a number of other properties available for fingerprinting the client. Each browser provides its own scripting environment and based on how the scripting environment interacts with scripts, the properties that are made available to scripts, and the specific values that are provided it is possible to get an accurate assessment of the browser and operating system.

2. Browser Scripting Environments

All major browsers support at least one scripting language. JavaScript is the scripting language that is typically supported, although some browsers may partially or fully support other languages such as JScript and Visual Basic Script (VBScript). Support for other languages within a browser is handled by the installation or inclusion of browser plug-ins, such as Java and ActionScript.

2.1. JavaScript

JavaScript is an implementation of the European Computer Manufacturers Association (ECMA) Specification 262. JavaScript was originally developed under the name of Mocha or LiveScript for the Netscape browser in 1995 (Netscape, 1995). The current version of JavaScript is 1.9 (ECMAScript version 5). However, most browsers do not support version 1.9 of JavaScript. They typically support at least version 1.3 (ECMAScript version 2).

2.1.1. Script Versions

JavaScript allows different versions of the scripting language to be executed depending upon the version of JavaScript (JavaScript Kit). Originally this allowed custom scripts to be executed based on the version of JavaScript, but since RFC4929 (Hoehrmann, 2006) this has been made obsolete. Most browsers still support the controlled execution of JavaScript versions despite the changes recommended by the RFC.


Script Tag

Browser Execution The browser executes the script with its default scripting engine and the default language.

<script language="javascript"></script>

The browser engine that is used to

Mark Fioravanti, mark.fioravanti.ii@gmail.com

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