CKAN is an open-source data management system for powering data hubs and data portals. There are a number of CKAN plugins, including XLoader, DataPusher, Resource proxy and ckanext-archiver, that work by downloading the contents of local or remote files in order to perform some actions with their contents (e.g. pushing to the DataStore, streaming contents or saving a local copy). All of them use the resource URL, and there are currently no checks to limit what URLs can be requested. This means that a malicious (or unaware) user can create a resource with a URL pointing to a place where they should not have access in order for one of the previous tools to retrieve it (known as a Server Side Request Forgery). Users wanting to protect against these kinds of attacks can use one or a combination of the following approaches: (1) Use a separate HTTP proxy like Squid that can be used to allow / disallow IPs, domains etc as needed, and make CKAN extensions aware of this setting via the ckan.download_proxy config option. (2) Implement custom firewall rules to prevent access to restricted resources. (3) Use custom validators on the resource url field to block/allow certain domains or IPs. All latest versions of the plugins listed above support the ckan.download_proxy settings. Support for this setting in the Resource Proxy plugin was included in CKAN 2.10.5 and 2.11.0.
The web server receives a URL or similar request from an upstream component and retrieves the contents of this URL, but it does not sufficiently ensure that the request is being sent to the expected destination.
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Ckan | Okfn | * | 2.10.5 (excluding) |