GHSA-95fc-g4gj-mqmx Steve doesn’t verify a server’s certificate and is susceptible to man-in-the-middle (MitM) attacks

• Go github.com/rancher/steve: >= 0.2.0, < 0.2.1 → fixed in 0.2.1 • Go github.com/rancher/steve: >= 0.3.0, < 0.3.3 → fixed in 0.3.3 • Go github.com/rancher/steve: >= 0.4.0, < 0.4.4 → fixed in 0.4.4 • Go github.com/rancher/steve: >= 0.5.0, < 0.5.13 → fixed in 0.5.13

Impact A vulnerability has been identified in Steve where by default it was using an insecure option that did not validate the certificate presented by the remote server while performing a TLS connection. This could allow the execution of a man-in-the-middle (MitM) attack against services using Steve. For example, Rancher relies on Steve as a dependency for its user interface (UI) to proxy requests to Kubernetes clusters. Users who have the permission to create a service in Rancher’s local cluster can take over Rancher’s UI and display their own UI to gather sensitive information. This is only possible when the setting `ui-offline-preferred` is manually set to `remote` (by default Rancher sets it to `dynamic`). This enables further attacks such as cross-site scripting (XSS), or tampering the UI to collect passwords from other users etc. Please consult the associated MITRE ATT&CK - Technique - Adversary-in-the-Middle for further information about this category of attack. Patches Patched versions of Steve include releases `v0.2.1`, `v0.3.3`, `v0.4.4` and `v0.5.13`. This vulnerability is addressed by changing Steve to always verify a server’s certificate based on Go’s TLS settings. Workarounds If you can't upgrade to a fixed version, please make sure that you are only using Steve to connect to trusted servers. References If you have any questions or comments about this advisory: • Reach out to the SUSE Rancher Security team for security related inquiries. • Open an issue in the Rancher repository. • Verify with our support matrix and product support lifecycle.