[CVE-2014-0046] XSS Vulnerability With {{link-to}} Helper in Non-block Form

[Tom Dale <tom () tomdale net>]

XSS Vulnerability With {{link-to}} Helper in Non-block Form

There is a vulnerability in the {{link-to}} helper in Ember.js. This
vulnerability
has been assigned CVE-2014-0046.

Versions Affected: 1.2.0, 1.2.1, 1.3.0, 1.3.1
Not affected: Versions prior to 1.2
Fixed Versions: 1.2.2, 1.3.2

Impact
-------

In general, Ember.js escapes or strips any user-supplied content before
inserting it in strings that will be sent to innerHTML.  However, a change
made
to the implementation of the {{link-to}} helper means that any user-supplied
data bound to the {{link-to}} helper's title attribute will not be escaped
correctly.

In applications that use the {{link-to}} helper in non-block form and bind
the title attribute to user-supplied content, a specially-crafted payload
could execute arbitrary JavaScript in the context of the current domain
("XSS").

All users running an affected release and binding user-supplied data to the
{{link-to}} helper's title attribute should either upgrade or use one of the
workarounds immediately.

Releases
--------

Releases are available on emberjs.com/builds/#/tagged

Workarounds
-----------

Ensure that you escape any user-supplied value that you bind to the
{{link-to}}
helper's title attribute. For example, if you bind a value named userTitle:

 {{link-to "user" title=userTitle}}

Ensure that you escape the value of userTitle using
Ember.Handlebars.Utils.escapeExpression:

 var userTitle = this.get('userTitle');
 var safeUserTitle = Ember.Handlebars.Utils.escapeExpression(userTitle);
 this.set('userTitle', safeUserTitle);

Patches
-------

Patches are available as an attachment to the announcement on the
emberjs-security list:

https://groups.google.com/forum/#!topic/ember-security/1h6FRgr8lXQ

Credits
-------

This vulnerability was reported to us by Hyder Ali of Zoho. Many thanks for
working with us on the patches and advisory.