CVE-2020-8558
The Kubelet and kube-proxy components in versions 1.1.0-1.16.10, 1.17.0-1.17.6, and 1.18.0-1.18.3 were found to contain a security issue which allows adjacent hosts to reach TCP and UDP services bound to 127.0.0.1 running on the node or in the node's network namespace. Such a service is generally thought to be reachable only by other processes on the same host, but due to this defeect, could be reachable by other hosts on the same LAN as the node, or by containers running on the same node as the service.
02 / AFFECTED SOFTWARE
Affected packages
41 explicit affected versions
03 / CONNECTIONS
Connected vulnerabilities
04 / EVIDENCE
Source records
A security issue was discovered in the Kubelet and kube-proxy components of Kubernetes which allows adjacent hosts to reach TCP and UDP services bound to 127.0.0.1 running on the node or in the node's network namespace. For example, if a cluster administrator runs a TCP service on a node that listens on 127.0.0.1:1234, because of this bug, that service would be potentially reachable by other hosts on the same LAN as the node, or by containers running on the same node as the service. If the example service on port 1234 required no additional authentication (because it assumed that only other localhost processes could reach it), then it could be vulnerable to attacks that make use of this bug.
Improper Authentication in Kubernetes in k8s.io/kubernetes
The Kubelet and kube-proxy components in versions 1.1.0-1.16.10, 1.17.0-1.17.6, and 1.18.0-1.18.3 were found to contain a security issue which allows adjacent hosts to reach TCP and UDP services bound to 127.0.0.1 running on the node or in the node's network namespace. Such a service is generally thought to be reachable only by other processes on the same host, but due to this defeect, could be reachable by other hosts on the same LAN as the node, or by containers running on the same node as the service.
05 / REFERENCES
Further evidence
- https://bugzilla.redhat.com/show_bug.cgi?id=1843358
- https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-8558
- https://github.com/bottlerocket-os/bottlerocket/security/advisories/GHSA-wqv3-8cm6-h6wg
- https://github.com/kubernetes/kubernetes
- https://github.com/kubernetes/kubernetes/issues/92315
- https://github.com/tabbysable/POC-2020-8558
- https://groups.google.com/g/kubernetes-announce/c/sI4KmlH3S2I/m/TljjxOBvBQAJ
- https://groups.google.com/g/kubernetes-security-announce/c/B1VegbBDMTE
- https://labs.bishopfox.com/tech-blog/bad-pods-kubernetes-pod-privilege-escalation
- https://nvd.nist.gov/vuln/detail/CVE-2020-8558
- https://security.netapp.com/advisory/ntap-20200821-0001
- https://www.openwall.com/lists/oss-security/2020/07/08/1
- https://security.netapp.com/advisory/ntap-20200821-0001/