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Difference between revisions of "List of useful HTTP headers"

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This page lists useful security-related HTTP headers. In most architectures these headers can be set in web server configuration ([ Apache], [ IIS], [ nginx]), without changing actual application's code. This offers significantly faster and cheaper method for at least partial mitigation of existing issues, and an additional layer of defense for new applications.
#redirect [[OWASP_Secure_Headers_Project]]
{| border="1"
! Header name
! Description
! Example
|[ Strict-Transport-Security]
|HTTP Strict-Transport-Security (HSTS) enforces secure (HTTP over SSL/TLS) connections to the server. This reduces impact of bugs in web applications leaking session data through cookies and external links and defends against Man-in-the-middle attacks. HSTS also disables the ability for user's to ignore SSL negotiation warnings.
|<code>Strict-Transport-Security: max-age=16070400; includeSubDomains</code>
| [ X-Frame-Options], [ Frame-Options]
| Provides [[Clickjacking]] protection. Values: ''deny'' - no rendering within a frame, ''sameorigin'' - no rendering if origin mismatch, ''allow-from: DOMAIN'' - allow rendering if framed by frame loaded from ''DOMAIN''
| <code> X-Frame-Options: deny</code>
| [ X-XSS-Protection]
| This header enables the [[Cross-site scripting]] (XSS) filter built into most recent web browsers. It's usually enabled by default anyway, so the role of this header is to re-enable the filter for this particular website if it was disabled by the user. This header is supported in IE 8+, and in Chrome (not sure which versions). The anti-XSS filter was added in Chrome 4. Its unknown if that version honored this header.
| <code>X-XSS-Protection: 1; mode=block</code>
| [ X-Content-Type-Options]
| The only defined value, "nosniff", prevents Internet Explorer and Google Chrome from MIME-sniffing a response away from the declared content-type. This also applies to [ Google Chrome], when downloading extensions. This reduces exposure to drive-by download attacks and sites serving user uploaded content that, by clever naming, could be treated by MSIE as executable or dynamic HTML files.
| <code> X-Content-Type-Options: nosniff </code>
|[ Content-Security-Policy, X-Content-Security-Policy, X-WebKit-CSP]
|[[Content Security Policy]] requires careful tuning and precise definition of the policy. If enabled, CSP has significant impact on the way browser renders pages (e.g., inline JavaScript disabled by default and must be explicitly allowed in policy). CSP prevents a wide range of attacks, including [[Cross-site scripting]] and other cross-site injections.
|<code>Content-Security-Policy: default-src 'self'</code>
| [ Content-Security-Policy-Report-Only]
| Like Content-Security-Policy, but only reports.  Useful during implementation, tuning and testing efforts.
| <code>Content-Security-Policy-Report-Only: default-src 'self'; report-uri</code>
==Check Your Headers==
Visit Check Your Headers to view and evaluate any website's security headers.
For Chrome, the Recx Security Analyser extension checks a number of security relevant headers and gives a nice report on the findings.
[ Recx Security Analyser]
==Real life examples==
Below examples present selected HTTP headers as set by popular websites to demonstrate that they are indeed being used in production services:
As of January 2013 [ Facebook] main page was setting these security related HTTP headers.
'''Strict-Transport-Security:''' max-age=60
'''X-Content-Type-Options:''' nosniff
'''X-Frame-Options:''' DENY
'''X-WebKit-CSP:''' <small><nowiki>default-src *; script-src https://*
  http://* https://* http://* *
  * * ** **
  'unsafe-inline' 'unsafe-eval' https://* http://*;
  style-src * 'unsafe-inline'; connect-src https://* http://*
  https://* http://* * **
  https://* ws://** http://*;</nowiki></small>
'''X-XSS-Protection:''' 1; mode=block
Especially interesting is Facebook's use of [ Content Security Policy] (using Google Chrome syntax), whose implementation can be [ challenging] for large sites with heavy usage of JavaScript.
As of July 2014, the following headers were set:
'''strict-transport-security: max-age=7776000'''
'''x-content-type-options: nosniff'''
'''x-frame-options: DENY'''
'''content-security-policy: <small><nowiki> default-src *;script-src https://* http://* https://* http://* *
* * ** ** 'unsafe-inline' 'unsafe-eval' https://* http://*
* chrome-extension://lifbcibllhkdhoafpjfnlhfpfgnpldfl;style-src * 'unsafe-inline';connect-src https://* http://*
https://* http://* * ** https://* wss://** ws://** http://** *;</nowiki></small>'''
As of January 2013 [ Google+] main page was setting these security related HTTP headers:
'''x-content-type-options:''' nosniff
'''x-frame-options:''' SAMEORIGIN
'''x-xss-protection:''' 1; mode=block
As of May 2013 [ Twitter] main page was setting these security related HTTP headers:
'''strict-transport-security:''' max-age=631138519
'''x-frame-options:''' SAMEORIGIN
'''x-xss-protection:''' 1; mode=block
As of July 2014 we can see the implementation of CSP added:
'''<nowiki>content-security-policy-report-only: default-src https:; connect-src https:; font-src https: data:; frame-src https:
http://* about: javascript:; img-src https: data:; media-src https:; object-src https:;
script-src 'unsafe-inline' 'unsafe-eval' about: https:; style-src 'unsafe-inline' https:; report-uri;</nowiki>'''

Latest revision as of 16:09, 26 May 2016