Advisories for Golang/Github.com/Rancher/Rancher/Server package

2022
2021
2019

Cross-site Scripting

Rancher is vulnerable to a Cross-Site Websocket Hijacking attack that allows an exploiter to gain access to clusters managed by Rancher. The attack requires a victim to be logged into a Rancher server, and then to access a third-party site hosted by the exploiter. Once that is accomplished, the exploiter is able to execute commands against the cluster's Kubernetes API with the permissions and identity of the victim.

Credentials Management

When Rancher starts for the first time, it creates a default admin user with a well-known password. After initial setup, the Rancher administrator may choose to delete this default admin user. If Rancher is restarted, the default admin user will be recreated with the well-known default password. An attacker could exploit this by logging in with the default admin credentials. This can be mitigated by deactivating the default admin user …

Improper Input Validation

A vulnerability exists in Rancher in the login component, where the errorMsg parameter can be tampered to display arbitrary content, filtering tags but not special characters or symbols. There's no other limitation of the message, allowing malicious users to lure legitimate users to visit phishing sites with scare tactics.

Improper Access Controls

In Rancher, unprivileged users (if allowed to deploy nodes) can gain admin access to the Rancher management plane because node driver options intentionally allow posting certain data to the cloud. The problem is that a user could choose to post a sensitive file such as /root/.kube/config or /var/lib/rancher/management-state/cred/kubeconfig-system.yaml.