Whitelist Guide

Domain whitelisting is a security model that controls access to external domains over which you application has no control. Cordova's default security policy allows access to any site. Before moving your application to production, you should formulate a whitelist and allow access to specific network domains and subdomains.

Cordova adheres to the W3C Widget Access specification, which relies on the <access> element within the app's config.xml file to enable network access to specific domains. For projects that rely on the CLI workflow described in The Command-Line Interface, this file is located in the project's top-level directory. Otherwise for platform-specific development paths, locations are listed in the sections below. (See the various Platform Guides for more information on each platform.)

The following examples demonstrate whitelist syntax:

This is the default value for newly created CLI projects.

Amazon Fire OS Whitelisting

Platform-specific whitelisting rules are found in res/xml/config.xml.

Android Whitelisting

Platform-specific whitelisting rules are found in res/xml/config.xml.

NOTE: On Android 2.3 and before, domain whitelisting only works for href hyperlinks, not referenced resources such as images and scripts. Take steps to avoid scripts from being injected into the application.

NOTE: In order to prevent external URLs such as mailto: from being opened in the Cordova webview as of Cordova 3.6.0, specifying origin="*" will implicity add rules for http and https protocols. If you require access to additional custom protocols, then you should also add them explicity to the whitelist. Also see "External Application Whitelist" below for more information on launching external applications by URL.

NOTE: Some network requests do not go through the Cordova Whitelist. This includes <video> and <audio> resouces, WebSocket connections (on Android 4.4+), and possibly other non-http requests. On Android 4.4+, you can include a CSP header in your HTML documents to restrict access to those resources. On older versions of Android, it may not be possible to restrict them.

External Application Whitelist

Cordova 3.6.0 introduces a second whitelist, for restricting which URLs are allowed to launch external applications. In previous versions of Cordova, all non-http URLs, such as mailto:, geo:, sms: and intent, were implicitly allowed to be the target of an <a> tag. Because of the potential for an application to leak information, if an XSS vulnerability allows an attacker to construct arbitrary links, these URLs must be whitelisted as well, starting in Cordova 3.6.0.

To allow a URL pattern to launch an external application, use an <access> tag in your config.xml file, with the launch-external attribute set.

Examples:

  • To allow links to send SMS messages:

    <access origin="sms:*" launch-external="yes" />
    
  • To allow links to open Maps:

    <access origin="geo:*" launch-external="yes" />
    
  • To allow links to example.com to open in an external browser:

    <access origin="http://example.com/*" launch-external="yes" />
    
  • To allow all non-whitelisted websites to open in an external browser: (This is the same as the previous behaviour for non-whitelisted URLs)

    <access origin="http://*" launch-external="yes" />
    <access origin="https://*" launch-external="yes" />
    
  • To allow access to all URLs, reverting to the Cordova 3.5.0 policy (not recommended):

    <access origin="*" launch-external="yes" />
    

When navigating to a URL from within your application, the interal whitelist is tested first, and if the URL is not whitelisted there, then the external whitelist is tested. This means that any http: or https: URLs which match both whitelists will be opened inside of the Cordova application, rather than launching the external browser.

iOS Whitelisting

The platform's whitelisting rules are found in the named application directory's config.xml file.

Origins specified without a protocol, such as www.apache.org rather than http://www.apache.org, default to all of the http, https, ftp, and ftps schemes.

Wildcards on the iOS platform are more flexible than in the W3C Widget Access specification. For example, the following accesses all subdomains and top-level domains such as .com and .net:

    <access origin="*.google.*" />

Unlike the Android platform noted above, navigating to non-whitelisted domains via href hyperlink on iOS prevents the page from opening at all.

BlackBerry 10 Whitelisting

The whitelisting rules are found in www/config.xml.

BlackBerry 10's use of wildcards differs from other platforms in two ways:

  • Any content accessed by XMLHttpRequest must be declared explicitly. Setting origin="*" does not work in this case. Alternatively, all web security may be disabled using the WebSecurity preference described in BlackBerry Configuration:

    <preference name="websecurity" value="disable" />
    
  • As an alternative to setting *.domain, set an additional subdomains attribute to true. It should be set to false by default. For example, the following allows access to google.com, maps.google.com, and docs.google.com:

    <access origin="http://google.com" subdomains="true" />
    

The following narrows access to google.com:

    <access origin="http://google.com" subdomains="false" />

Specify access to all domains, including the local file:// protocol:

<access origin="*" subdomains="true" />

(For more information on support, see BlackBerry's documentation on the access element.)

iOS Changes in 3.1.0

Prior to version 3.1.0, Cordova-iOS included some non-standard extensions to the domain whilelisting scheme supported by other Cordova platforms. As of 3.1.0, the iOS whitelist now conforms to the resource whitelist syntax described at the top of this document. If you upgrade from pre-3.1.0, and you were using these extensions, you may have to change the config.xml file in order to continue whitelisting the same set of resources as before.

Specifically, these patterns need to be updated:

  • "apache.org" (no protocol): This would previously match http, https, ftp, and ftps protocols. Change to "*://apache.org/*" to include all protocols, or include a line for each protocol you need to support.

  • "http://apache.*" (wildcard at end of domain): This would previously match all top-level-domains, including all possible two-letter TLDs (but not useful domains like .co.uk). Include a line for each TLD which you actually control, and need to whitelist.

  • "h*t*://ap*he.o*g" (wildcards for random missing letters): These are no longer supported; change to include a line for each domain and protocol that you actually need to whitelist.

Windows Phone Whitelisting

The whitelisting rules for Windows Phone 8 are found in the app's config.xml file.

Tizen Whitelisting

Whitelisting rules are found in the app's config.xml file. The platform relies on the same subdomains attribute as the BlackBerry platform. (For more information on support, see Tizen's documentation on the access element.)