Headline
CVE-2021-20238: unauthenticated access to Machine Config Server ignition config
It was found in OpenShift Container Platform 4 that ignition config, served by the Machine Config Server, can be accessed externally from clusters without authentication. The MCS endpoint (port 22623) provides ignition configuration used for bootstrapping Nodes and can include some sensitive data, e.g. registry pull secrets. There are two scenarios where this data can be accessed. The first is on Baremetal, OpenStack, Ovirt, Vsphere and KubeVirt deployments which do not have a separate internal API endpoint and allow access from outside the cluster to port 22623 from the standard OpenShift API Virtual IP address. The second is on cloud deployments when using unsupported network plugins, which do not create iptables rules that prevent to port 22623. In this scenario, the ignition config is exposed to all pods within the cluster and cannot be accessed externally.
Note: If your use of the APIs is failing with an error titled ‘API access must use the Authorization header’ then you need to read the API Authentication changes announcement
Bug 1926568 (CVE-2021-20238) - CVE-2021-20238 openshift/machine-config-operator: unauthenticated access to Machine Config Server ignition config
Summary: CVE-2021-20238 openshift/machine-config-operator: unauthenticated access to M…
Keywords:
Status:
NEW
Alias:
CVE-2021-20238
Product:
Security Response
Classification:
Other
Component:
vulnerability
Sub Component:
Version:
unspecified
Hardware:
All
OS:
Linux
Priority:
medium
Severity:
medium
Target Milestone:
—
Assignee:
Red Hat Product Security
QA Contact:
Docs Contact:
URL:
Whiteboard:
Depends On:
1925494
Blocks:
1926028 1965031
TreeView+
depends on / blocked
Reported:
2021-02-09 04:38 UTC by Sam Fowler
Modified:
2022-01-08 05:28 UTC (History)
CC List:
19 users (show)
Fixed In Version:
Doc Type:
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Doc Text:
It was found in OpenShift Container Platform 4 that ignition config, served by the Machine Config Server, can be accessed externally from clusters without authentication. The MCS endpoint (port 22623) provides ignition configuration used for bootstrapping Nodes and can include some sensitive data, e.g. registry pull secrets. There are two scenarios where this data can be accessed. The first is on Baremetal, OpenStack, Ovirt, Vsphere and KubeVirt deployments which do not have a separate internal API endpoint and allow access from outside the cluster to port 22623 from the standard OpenShift API Virtual IP address. The second is on cloud deployments when using unsupported network plugins, which do not create iptables rules that prevent to port 22623. In this scenario, the ignition config is exposed to all pods within the cluster and cannot be accessed externally.
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