9.9 High
CVSS3
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
LOW
User Interaction
NONE
Scope
CHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
0.001 Low
EPSS
Percentile
38.3%
A failure in the update logic of Rancher’s admission Webhook may lead to the misconfiguration of the Webhook. This component enforces validation rules and security checks before resources are admitted into the Kubernetes cluster.
When the Webhook is operating in a degraded state, it no longer validates any resources, which may result in severe privilege escalations and data corruption.
The issue only affects users that upgrade from 2.6.x
or 2.7.x
to 2.7.2
. Users that did a fresh install of 2.7.2 (and did not follow an upgrade path) are not affected.
The command below can be executed on the local
cluster to determine whether the cluster is affected by this issue:
$ kubectl get validatingwebhookconfigurations.admissionregistration.k8s.io rancher.cattle.io
NAME WEBHOOKS AGE
rancher.cattle.io 0 19h
If the resulting webhook quantity is 0
, the Rancher instance is affected.
Patched versions include release 2.7.3
and later versions.
If you are affected and cannot update to a patched Rancher version, the recommended workaround is to manually reconfigure the Webhook with the script below. Please note that the script must be run from inside the local
cluster or with a kubeconfig pointing to the local
cluster which has admin permissions.
#!/bin/bash
set -euo pipefail
function prereqs() {
if ! [ -x "$(command -v kubectl)" ]; then
echo "error: kubectl is not installed." >&2
exit 1
fi
if [[ -z "$(kubectl config view -o jsonpath='{.clusters[].cluster.server}')" ]]; then
echo "error: No kubernetes cluster found on kubeconfig." >&2
exit 1
fi
}
function restart_deployment(){
kubectl rollout restart deployment rancher-webhook -n cattle-system
kubectl rollout status deployment rancher-webhook -n cattle-system --timeout=30s
}
function workaround() {
echo "Cluster: $(kubectl config view -o jsonpath='{.clusters[].cluster.server}')"
if ! kubectl get validatingwebhookconfigurations.admissionregistration.k8s.io rancher.cattle.io > /dev/null 2>&1; then
echo "webhook rancher.cattle.io not found, restarting deployment:"
restart_deployment
echo "waiting for webhook configuration"
sleep 15s
fi
local -i webhooks
webhooks="$(kubectl get validatingwebhookconfigurations.admissionregistration.k8s.io rancher.cattle.io --no-headers | awk '{ print $2 }')"
if [ "${webhooks}" == "0" ]; then
echo "Webhook misconfiguration status: Cluster is affected by CVE-2023-22651"
echo "Running workaround:"
kubectl delete validatingwebhookconfiguration rancher.cattle.io
restart_deployment
ret=$?
if [ $ret -eq 0 ]; then
echo "Webhook restored, CVE-2023-22651 is fixed"
else
echo "error trying to restart deployment. try again in a few seconds."
fi
else
echo "Webhook misconfiguration status: not present (skipping)"
fi
echo "Done"
}
function main() {
prereqs
workaround
}
main
If you have any questions or comments about this advisory:
CPE | Name | Operator | Version |
---|---|---|---|
github.com/rancher/rancher | eq | 2.7.2 |