If an attacker is able to convince a victim to visit a URL referencing a vulnerable page, arbitrary JavaScript content may be executed within the context of the victim’s browser.
The user visiting the malicious link must be unauthenticated, and the link must be for a page that contains the login button in the menu bar.
There are two ways an unauthenticated user can open a page in Grafana that contains the login button:
- Anonymous authentication is enabled. This means all pages in Grafana would be open for the attack.
- The link is to an unauthenticated page. The following pages are vulnerable:
/dashboard-solo/snapshot/*/dashboard/snapshot/*/invite/:code
The url has to be crafted to exploit AngularJS rendering and contain the interpolation binding for AngularJS expressions. AngularJS uses double curly braces for interpolation binding: {{ }}
An example of an expression would be: {{constructor.constructor(‘alert(1)’)()}}. This can be included in the link URL like this:
https://play.grafana.org/dashboard/snapshot/%7B%7Bconstructor.constructor('alert(1)')()%7D%7D?orgId=1
When the user follows the link and the page renders, the login button will contain the original link with a query parameter to force a redirect to the login page. The URL is not validated, and the AngularJS rendering engine will execute the JavaScript expression contained in the URL.