CVE-2022-31107

Grafana is an open-source platform for monitoring and observability. In versions 5.3 until 9.0.3, 8.5.9, 8.4.10, and 8.3.10, it is possible for a malicious user who has authorization to log into a Grafana instance via a configured OAuth IdP which provides a login name to take over the account of another user in that Grafana instance. This can occur when the malicious user is authorized to log in to Grafana via OAuth, the malicious users external user id is not already associated with an account in Grafana, the malicious users email address is not already associated with an account in Grafana, and the malicious user knows the Grafana username of the target user. If these conditions are met, the malicious user can set their username in the OAuth provider to that of the target user, then go through the OAuth flow to log in to Grafana. Due to the way that external and internal user accounts are linked together during login, if the conditions above are all met then the malicious user will be able to log in to the target users Grafana account. Versions 9.0.3, 8.5.9, 8.4.10, and 8.3.10 contain a patch for this issue. As a workaround, concerned users can disable OAuth login to their Grafana instance, or ensure that all users authorized to log in via OAuth have a corresponding user account in Grafana linked to their email address.

Weakness

The product performs an authorization check when an actor attempts to access a resource or perform an action, but it does not correctly perform the check. This allows attackers to bypass intended access restrictions.

Affected Software

Extended Description

Assuming a user with a given identity, authorization is the process of determining whether that user can access a given resource, based on the user’s privileges and any permissions or other access-control specifications that apply to the resource. When access control checks are incorrectly applied, users are able to access data or perform actions that they should not be allowed to perform. This can lead to a wide range of problems, including information exposures, denial of service, and arbitrary code execution.

Potential Mitigations

• Divide the product into anonymous, normal, privileged, and administrative areas. Reduce the attack surface by carefully mapping roles with data and functionality. Use role-based access control (RBAC) [REF-229] to enforce the roles at the appropriate boundaries.
• Note that this approach may not protect against horizontal authorization, i.e., it will not protect a user from attacking others with the same role.
• Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
• For example, consider using authorization frameworks such as the JAAS Authorization Framework [REF-233] and the OWASP ESAPI Access Control feature [REF-45].
• For web applications, make sure that the access control mechanism is enforced correctly at the server side on every page. Users should not be able to access any unauthorized functionality or information by simply requesting direct access to that page.
• One way to do this is to ensure that all pages containing sensitive information are not cached, and that all such pages restrict access to requests that are accompanied by an active and authenticated session token associated with a user who has the required permissions to access that page.

References

• https://github.com/grafana/grafana/security/advisories/GHSA-mx47-6497-3fv2
• https://grafana.com/docs/grafana/next/release-notes/release-notes-8-4-10/
• https://grafana.com/docs/grafana/next/release-notes/release-notes-8-5-9/
• https://grafana.com/docs/grafana/next/release-notes/release-notes-9-0-3/
• https://security.netapp.com/advisory/ntap-20220901-0010/