Difference between revisions of "HTTP Strict Transport Security"

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(Change made re: implementation in IIS after seeking approval from the original page author Michael Coates.)
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The specification has been released and published end of 2012 as RFC 6797 (HTTP Strict Transport Security (HSTS)) by the IETF. (Reference see in the links at the bottom.)
  
 
== Examples  ==
 
== Examples  ==
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Example of the HTTP strict transport security header  
 
Example of the HTTP strict transport security header  
  
   Strict-Transport-Security: max-age=60000
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   Strict-Transport-Security: max-age=31536000
  
If all subdomains are HTTPS to then the following header is applicable:
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If all subdomains are HTTPS too then the following header is applicable:
  
   Strict-Transport-Security: max-age=60000; includeSubDomains
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   Strict-Transport-Security: max-age=31536000; includeSubDomains
  
 
== Browser Support ==
 
== Browser Support ==
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|-
 
|-
 
| Safari<br>
 
| Safari<br>
| ??<br>
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| Mavericks (Mac OS X 10.9)<br>
 
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| Chrome<br>
 
| Chrome<br>
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On the HTTPS site configuration the following is needed to add the header as [http://tools.ietf.org/html/draft-ietf-websec-strict-transport-sec#section-6.1 recommended by the standard]:
 
On the HTTPS site configuration the following is needed to add the header as [http://tools.ietf.org/html/draft-ietf-websec-strict-transport-sec#section-6.1 recommended by the standard]:
         Header set Strict-Transport-Security "max-age=16070400; includeSubDomains"
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         Header set Strict-Transport-Security "max-age=31536000; includeSubDomains"
  
The following links show how to do set response headers in other web servers:
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The following links show how to set response headers in other web servers:
 
* [http://wiki.nginx.org/HttpHeadersModule NGINX]
 
* [http://wiki.nginx.org/HttpHeadersModule NGINX]
 
* [http://redmine.lighttpd.net/wiki/lighttpd/Docs:ModSetEnv#Options Lighttpd]
 
* [http://redmine.lighttpd.net/wiki/lighttpd/Docs:ModSetEnv#Options Lighttpd]
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[http://dev.chromium.org/sts Chromium Projects/HSTS]
 
[http://dev.chromium.org/sts Chromium Projects/HSTS]
  
[http://tools.ietf.org/html/draft-ietf-websec-strict-transport-sec HSTS Spec]
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[http://tools.ietf.org/html/rfc6797 HSTS Spec]
  
 
[http://en.wikipedia.org/wiki/HTTP_Strict_Transport_Security Wikipedia]
 
[http://en.wikipedia.org/wiki/HTTP_Strict_Transport_Security Wikipedia]
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[http://lists.w3.org/Archives/Public/public-webapps/2009JulSep/1148.html Google Chrome STS Support]
 
[http://lists.w3.org/Archives/Public/public-webapps/2009JulSep/1148.html Google Chrome STS Support]
  
 
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[http://www.thoughtcrime.org/software/sslstrip/ Moxie Marlinspike's Black Hat 2009 talk on sslstrip, that demonstrates why you need HSTS]
  
 
[[Category:Control|Control]]
 
[[Category:Control|Control]]

Latest revision as of 16:15, 15 April 2014


Contents

Description

HTTP Strict Transport Security (HSTS) is an opt-in security enhancement that is specified by a web application through the use of a special response header. Once a supported browser receives this header that browser will prevent any communications from being sent over HTTP to the specified domain and will instead send all communications over HTTPS. It also prevents HTTPS click through prompts on browsers.


The specification has been released and published end of 2012 as RFC 6797 (HTTP Strict Transport Security (HSTS)) by the IETF. (Reference see in the links at the bottom.)

Examples

Example of the HTTP strict transport security header

 Strict-Transport-Security: max-age=31536000

If all subdomains are HTTPS too then the following header is applicable:

 Strict-Transport-Security: max-age=31536000; includeSubDomains

Browser Support

Browser
Support Introduced
Internet Explorer
no support as of IE 10 (tested on 2013-01-01)
Firefox
4
Opera
12
Safari
Mavericks (Mac OS X 10.9)
Chrome
4.0.211.0


Server Side

The web server side needs to inject the HSTS header.

For HTTP sites on the same domain it is not recommended to add a HSTS header but to do a permanent redirect (301 status code) to the HTTPS site.

An Apache HTTPd example that will permanently redirect a URL to the identical URL with a HTTPS scheme, is as follows:

<VirtualHost *:80>
       ServerAlias *
       RewriteEngine On
       RewriteRule ^(.*)$ https://%{HTTP_HOST}$1 [redirect=301]
</VirtualHost>

On the HTTPS site configuration the following is needed to add the header as recommended by the standard:

       Header set Strict-Transport-Security "max-age=31536000; includeSubDomains"

The following links show how to set response headers in other web servers:

IIS

Whilst custom headers can be configured in IIS without any extensions, it is not possible to restrict these headers to secure transport channels as per the HSTS specification. HSTS has been implemented as per the specification as an open source IIS module.

Threats

HSTS addresses the following threats:

  • User bookmarks or manually types http://example.com and is subject to a man-in-the-middle attacker
    • HSTS automatically upgrades HTTP requests to HTTPS for the target domain
  • Web application that is intended to be purely HTTPS inadvertently contains HTTP links or serves content over HTTP
    • HSTS automatically upgrades HTTP requests to HTTPS for the target domain
  • A man-in-the-middle attacker attempts to intercept traffic from a victim user using an invalid certificate and hopes the user will accept the bad certificate
    • HSTS does not allow a user to override the invalid certificate message


Links

Chromium Projects/HSTS

HSTS Spec

Wikipedia

Mozilla Developer Network

OWASP TLS Protection Cheat Sheet

Firefox STS Support

Google Chrome STS Support

Moxie Marlinspike's Black Hat 2009 talk on sslstrip, that demonstrates why you need HSTS