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 within Rancher Manager in the GitHub App authentication provider. When evaluating permissions, the provider incorrectly expands user team memberships to include all teams within the associated GitHub organization, rather than restricting access to the specific teams to which the user actually belongs.

Specifically, when a user authenticates via the GitHub App provider, Rancher's team membership evaluation logic incorrectly handles cached data. Instead of checking the user-specific list, the evaluation logic iterates over all teams defined within the entire GitHub organization. The authentication provider should consult the correctly cached, per-user membership list to assign the user's specific group permissions. Consequently, any authenticated user who belongs to at least one team in a GitHub organization is mistakenly granted group principals for every team within that entire organization during authentication and authorization checks.

This issue allows a malicious user who is a member of a low-privilege team within a GitHub organization to gain unauthorized access to or permissions for any other team in that organization. If those other teams are bound to Rancher login allowlists or RBAC roles (cluster-level, project-level, or global), the attacker can pass access checks that should otherwise fail, inheriting permissions they were never granted.

Exploitation of this vulnerability requires the following conditions to be met: - The GitHub App authentication provider must be enabled and configured for the target GitHub organization. - The attacker must possess a valid GitHub account with membership in at least one team within that target organization. - A separate team within the same GitHub organization must be explicitly mapped to Rancher RBAC roles or specified within Rancher's login allowlist (allowedPrincipalIds).

Please consult the associated MITRE ATT&CK - Technique - Valid Accounts for further information about this category of attack.

Patches This fix corrects the team listing logic to iterate only the teams stored in the per-user membership cache and includes a one-time startup migration that marks all affected User resources for refresh, forcing Rancher to rebuild group principals using the now-corrected logic.

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

Workarounds If upgrading to a patched version immediately is not feasible, users are encouraged to consider these temporary mitigations: - Disable GitHub App authentication provider and switch to an alternative authentication provider (GitHub OAuth). - Remove or restrict team-based group principals from allowed principalIds. - Audit and temporarily remove RBAC bindings (GlobalRoleBindings, ClusterRoleTemplateBindings, ProjectRoleTemplateBindings) that reference GitHub App team principals until the patch is applied. - Disable provider refresh and clean up inflated group membership for users (manually or by writing a script).

These workarounds reduce the attack surface but do not eliminate the vulnerability. Existing user sessions and cached principals remain inflated until a provider refresh occurs. Upgrading to a patched version is strongly recommended.

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 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.