Bug 1946538 (CVE-2021-25736) - CVE-2021-25736 kubernetes: LoadBalancer Service type don't create a HNS policy for empty or invalid external loadbalancer IP, what could lead to MITM
Summary: CVE-2021-25736 kubernetes: LoadBalancer Service type don't create a HNS polic...
Keywords:
Status: CLOSED ERRATA
Alias: CVE-2021-25736
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
medium
medium
Target Milestone: ---
Assignee: Red Hat Product Security
QA Contact:
URL:
Whiteboard:
Depends On: 1946628
Blocks: 1918517
TreeView+ depends on / blocked
 
Reported: 2021-04-06 11:23 UTC by Przemyslaw Roguski
Modified: 2021-06-23 10:40 UTC (History)
7 users (show)

Fixed In Version: kubernetes 1.21.0, kubernetes 1.20.6, kubernetes 1.19.10, kubernetes 1.18.18
Doc Type: ---
Doc Text:
A flaw was found in the Windows kube-proxy component. In a cloud environment that does not set the “.status.loadBalancer.ingress.ip” field in the LoadBalancer service status configuration (for example in AWS) the packets can be misrouted and reach an unintended destination.
Clone Of:
Environment:
Last Closed: 2021-06-23 10:40:27 UTC
Embargoed:

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System ID Private Priority Status Summary Last Updated
Red Hat Product Errata RHSA-2021:2130 0 None None None 2021-06-23 05:38:02 UTC

Description Przemyslaw Roguski 2021-04-06 11:23:19 UTC 
In Windows kube-proxy component when a service of type “LoadBalancer” is created, packets can be misrouted and reach an unintended destination.
This issue can be only observed on any cloud environment that does not set the “.status.loadBalancer.ingress.ip” field in the LoadBalancer service status configuration. For one example, Kubernetes environments integrating with AWS cloud load balancers are impacted as they currently set “.status.loadBalancer.ingress.hostname” instead.
This could leading to potential MITM attack.
Comment 1 Przemyslaw Roguski 2021-04-06 11:23:24 UTC 
Acknowledgments:

Name: Eric Paris (Red Hat), Christian Hernandez (Red Hat)
Comment 5 Sam Fowler 2021-05-11 07:23:36 UTC 
External References:

https://groups.google.com/g/kubernetes-security-announce/c/lIoOPObO51Q
Comment 6 Przemyslaw Roguski 2021-05-11 07:33:31 UTC 
Statement:

Clusters where the LoadBalancer controller sets the “status.loadBalancer.ingress[].ip” field are unaffected.
Comment 7 errata-xmlrpc 2021-06-23 05:38:02 UTC 
This issue has been addressed in the following products:

  Red Hat OpenShift Container Platform 4.7

Via RHSA-2021:2130 https://access.redhat.com/errata/RHSA-2021:2130
Comment 8 Product Security DevOps Team 2021-06-23 10:40:27 UTC 
This bug is now closed. Further updates for individual products will be reflected on the CVE page(s):

https://access.redhat.com/security/cve/cve-2021-25736
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