AutoCSP is not just another tool to generate a valid Content Security Policy header for your current webpage. Also is a didactic tool to understand all the available ways to increase the security of your web page.
With AutoCSP you can generate:
- Content-Security-Policy headers
- Nonce references
- Subresource integrity hashes
- Inline script hashes
Basically, it analizes your DOM tags looking for sources for all the rules:
- default-src:
- script-src:
- style-src:
- img-src:
- child-src:
- media-src:
- object-src:
Not supported yet:
- font-src:
- connect-src:
Go to you webpage, open the browser inspector and include the minified version of this library in your DOM manually.
<script src="http://cdn..../autocsp.min.js"></script>If your are using jQuery in your webpage you can run this:
$.getScript("http://cdn..../autocsp.min.js");After load this library in your webpage context, then you can start to analyze your webpage. Run the code below:
AutoCSP.rule();and you will get a console output like this:
Content-Security-Policy: default-src 'none'; script-src 'self' www.google-analytics.co www.googletagmanager.co i.kissmetrics.co cdn.ravenjs.co 'sha256-faDewrRjLN6HVr4qFb34mLsJTMWzibMGtolRQsuqEB0=' 'sha256-Dvu64ENYzDEkDpriV+KtNqfahz95IoNI4db+QIp9F+g='; style-src 'self' fonts.googleapis.co; img-src 'self' secure.gravatar.co; child-src 'none'; font-src 'self'; connect-src 'self'; media-src 'none'; object-src 'none';
Note: It's important to understand that this should not be the common flow to create this header for your web page. When you start creating a webpage, you need to control all the orgins where you resquest from, instead of generate them afterwards. However, for projects that have not controlled their source origins in the past, this tool could be useful to spot them.
By default, AutoCSP generates all the hashes with sha256 algorithm but you
can change it to one of the availble ones:
- sha1
- sha256 * Default
- sha384
- sha512
Example:
AutoCSP.setup('sha384');CSP Level 2 added backward compatibility for inline scripts by allowing you to whitelist specific inline scripts using either a cryptographic nonce (number used once) or a hash. As we said before, with AutoCSP you can get all current hashes:
AutoCSP.hashes();
If your are loading third-party JavaScript and you want to prevent unexpected or malicious modifications, we recomend to you add Subresource Integrity checks to all your script tags.
With this feature you can be sure that your webpage will not be compromised if one ore more scripts in your Content Delivery Networks (CDNs) get modified without authorization.
<script src="https://cdnjs.cloudflare.com/ajax/libs/underscore.js/1.8.3/underscore-min.js" integrity="sha384-FZY+KSLVXVyc1qAlqH9oCx1JEOlQh6iXfw3o2n3Iy32qGjXmUPWT9I0Z9e9wxYe3" crossorigin="anonymous"></script>In this example, we are inclouding Underscore library,
from CloudFlare CDN and we can be sure that we are loading the code that we
trust and match with
sha384-FZY+KSLVXVyc1qAlqH9oCx1JEOlQh6iXfw3o2n3Iy32qGjXmUPWT9I0Z9e9wxYe3 hash.
In AutoCSP you can generate all Subresource Integrity hashes for your third party scripts all at the same time. Just run:
AutoCSP.integrities();
- Detect font-src urls: preliminary support added to detect .woff and .woff2, but it is not very stable.
- Detect connect urls: we need to analyze XHR traffic
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Copyright (c) 2016 Ferran Basora fcsonline@gmail.com
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