A SAML authentication replay vulnerability in Rancher's Assertion Consumer Service (ACS) handler did not enforce one-time use of SAML assertion, potentially allowing person in the middle attacks against Rancher, affecting Rancher 2.14.0 before 2.14.3,

Impact

A vulnerability has been identified in Rancher Manager that allows users assigned the Project Owner role to modify Pod Security Admission (PSA) labels on namespaces within their projects. Under the default role configuration, an attacker with the following access pattern can exploit this issue: 1. Cluster Access: The user is granted Cluster Member access. 2. Project Ownership: The user creates or is assigned ownership of a project. 3. Namespace Creation: The user creates a namespace within that project. 4. PSA Modification: The user modifies the namespace PSA configuration to use the privileged profile. 5. Privilege Escalation: The user deploys privileged workloads within the namespace.

As outlined in the Kubernetes Pod Security Standards documentation, privileged containers disable core Kubernetes security protections, allowing workloads to bypass standard container isolation boundaries. This can result in privilege escalation within the cluster environment.

Potential impacts include: - Deployment of privileged containers - Access to host-level resources - Container breakout - Cluster privilege escalation - Compromise of workloads running on affected nodes

Please refer to the associated MITRE ATT&CK techniques for further information about this category of attack: - Deploy Container - Escape to Host - Exploitation for Privilege Escalation

Reference: Kubernetes Pod Security Standards — Privileged Profile

Patches This vulnerability is resolved by modifying the project-owner role to explicitly define the allowed verbs for projects resources instead of using the wildcard () permission.

The updated role configuration removes access to the updatepsa verb. This prevents project owners from modifying PSA settings in a manner that could enable privilege escalation.

Patched versions of Rancher include releases v2.12.10, v2.13.6, and v2.14.2.

Workarounds If upgrading is not immediately possible, administrators should create a custom project role based on the existing Project Owner role, while removing unrestricted wildcard permissions for project resources.

The allowed verbs for projects should be restricted to: “get, update, delete, patch, create, list, watch, deletecollection” instead of “”.

This prevents access to the updatepsa capability that enables the privilege escalation path.

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.

Impact A vulnerability has been identified within Rancher Manager, where using self-signed CA certificates and passing the -skip-verify flag to the Rancher CLI login command without also passing the –cacert flag results in the CLI attempting to fetch CA certificates stored in Rancher’s setting cacerts. This does not apply to any other commands and only applies to the login command if the –cacert flag was not provided.

An attacker with network-level access between the Rancher CLI and Rancher Manager could interfere with the TLS handshake to return a CA they control, despite the use of the --skip-verify flag. This may be abused to bypass TLS as a security control. Attackers can also see basic authentication headers in a Man-in-the-Middle due to the lack of TLS enforcement.

Please consult the associated MITRE ATT&CK - Technique - Man-in-the-Middle for further information about this category of attack.

Patches This vulnerability is addressed by removing the ability to fetch CA certificates stored in Rancher’s setting cacerts when using the login command. Whenever required, for example when using self-signed certificates, CA certificates have to be explicitly passed with the –cacert flag.

Patched versions of Rancher include releases v2.13.2, v2.12.6, v2.11.10, and v2.10.11.

Workarounds If a projecct can't upgrade to a fixed version, please make sure whenever required, for example when using self-signed certificates, to always explicitly pass CA certificates with the –cacert flag when using the login command.

References If there are 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 the support matrix and product support lifecycle.

Note: Rancher versions beyond 2.3.0-alpha5 are no longer supported at pkg.go.dev, follow Rancher installation instructions for newer versions.