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CORS Essentials

You're reading from   CORS Essentials Access web resources on different domains

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Product type Paperback
Published in May 2017
Publisher
ISBN-13 9781784393779
Length 144 pages
Edition 1st Edition
Languages
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Author (1):
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Rajesh Gunasundaram Rajesh Gunasundaram
Author Profile Icon Rajesh Gunasundaram
Rajesh Gunasundaram
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Table of Contents (10) Chapters Close

Preface 1. Why You Need CORS FREE CHAPTER 2. Creating Proxies for CORS 3. Usability and Security 4. CORS in Popular Content Management Frameworks 5. CORS in Windows 6. CORS in the Cloud 7. CORS in Node.js 8. CORS Best Practices Index

Enhancing security in CORS


CORS by itself does not provide any security, except for the domain allowed in the Access-Control-Allow-Origin header.

Some recommended practices for better security when using CORS are as follows:

  • Place the CORS header only on page(s) that need it; do not add the header across site

  • Use Access-Control-Allow-Origin: * only for publicly accessible static resources that do not include sensitive information or modify data

Limiting access when using the Access-Control-Allow-Origin, * wildcard

Although the CORS specification suggests that a list of allowed domains may be provided, in practice, very few clients support a list of allowed domains. Therefore, if you need to allow more than one domain, you must allow all domains with the Access-Control-Allow-Origin, * wildcard. Then, any domain, even the ones that are not intended, can make a CORS request to the page with the header.

You must provide additional security when using the wildcard if you want to prevent CORS requests...

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