Portworx Half-Blind SSRF in kube-controller-manager
A half-blind Server Side Request Forgery (SSRF) vulnerability exists in kube-controller-manager when using the in-tree Portworx StorageClass. This vulnerability allows authorized users to leak arbitrary information from unprotected endpoints in the control plane’s host network (including link-local or loopback services).
Nodes can delete themselves by adding an OwnerReference
A vulnerability exists in the NodeRestriction admission controller in Kubernetes clusters where node users can delete their corresponding node object by patching themselves with an OwnerReference to a cluster-scoped resource. If the OwnerReference resource does not exist or is subsequently deleted, the given node object will be deleted via garbage collection.
A security issue was discovered in Kubernetes where a large number of container checkpoint requests made to the unauthenticated kubelet read-only HTTP endpoint may cause a Node Denial of Service by filling the Node's disk.
As mitigations to a report from 2019 and CVE-2020-8555, Kubernetes attempts to prevent proxied connections from accessing link-local or localhost networks when making user-driven connections to Services, Pods, Nodes, or StorageClass service providers. As part of this mitigation Kubernetes does a DNS name resolution check and validates that response IPs are not in the link-local (169.254.0.0/16) or localhost (127.0.0.0/8) range. Kubernetes then performs a second DNS resolution without validation for the actual connection. If a non-standard DNS server returns different non-cached responses, a user may be able to bypass the proxy IP restriction
Holes in EndpointSlice Validation Enable Host Network Hijack
A security issue was discovered with Kubernetes that could enable users to send network traffic to locations they would otherwise not have access to via a confused deputy attack.
A security issue was discovered in Kubernetes where actors that control the responses of MutatingWebhookConfiguration or ValidatingWebhookConfiguration requests are able to redirect kube-apiserver requests to private networks of the apiserver. If that user can view kube-apiserver logs when the log level is set to 10, they can view the redirected responses and headers in the logs.
Kubernetes man in the middle using LoadBalancer or ExternalIPs
Kubernetes API server in all versions allow an attacker who is able to create a ClusterIP service and set the spec.externalIPs field, to intercept traffic to that IP address. Additionally, an attacker who is able to patch the status (which is considered a privileged operation and should not typically be granted to users) of a LoadBalancer service can set the status.loadBalancer.ingress.ip to similar effect.