A security issue has been found in Grafana before version 8.2.3. 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.
Vulmon
A security issue has been found in Grafana before version 8.2.3. 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.
https://github.com/grafana/grafana/security/advisories/GHSA-3j9m-hcv9-rpj8 https://github.com/grafana/grafana/commit/5c7224eb56801b22848470a50b50398bc06cc1e8
Workaround
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To mitigate the issue, a reverse proxy or similar can be used to block access to block the literal string "{{" in the path.