capgo.app is an over-the-air (OTA) update platform for Capacitor apps. In all versions up to and including the current release (no patch available at time of publication), the transfer_app() database function transfers an app, its channels, versions and related records to a destination organization without deleting or revalidating existing rows in channel_permission_overrides. As a result, a user who legitimately held a channel permission override while a member of the source organization retains that override after the transfer, even though they have no membership and no RBAC binding in the destination organization. Using their own authenticated JWT against the PostgREST API, such a former member can modify the destination-owned channel to point at a different bundle, causing the /updates endpoint to serve an attacker-selected application version to devices. The previously proposed fix for GHSA-626c-p6fq-3whq (PR #3093), which validates organization membership when an override is created or updated, does not remove overrides that became stale as a result of an app transfer.
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.
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.