[<prev] [next>] [day] [month] [year] [list]
Date: Tue, 18 May 2021 12:28:20 -0700
From: CJ Cullen <cjcullen@...gle.com>
To: oss-security@...ts.openwall.com
Subject: [kubernetes] CVE-2021-25737: Holes in EndpointSlice Validation Enable
Host Network Hijack
A security issue was discovered in Kubernetes where a user may be able to
redirect pod traffic to private networks on a Node. Kubernetes already
prevents creation of Endpoint IPs in the localhost or link-local range, but
the same validation was not performed on EndpointSlice IPs.
*This issue has been rated Low
(CVSS:3.0/AV:N/AC:L/PR:H/UI:N/S:U/C:L/I:N/A:N
<https://www.first.org/cvss/calculator/3.0#CVSS:3.0/AV:N/AC:L/PR:H/UI:N/S:U/C:L/I:N/A:N>),
and assigned CVE-2021-25737.*Affected Component
*kube-apiserver*Affected Versions
* - v1.21.0- v1.20.0 - v1.20.6- v1.19.0 - v1.19.10- v1.16.0 - v1.18.18
(Note: EndpointSlices were not enabled by default in 1.16-1.18)*Fixed
Versions
*This issue is fixed in the following versions: - v1.21.1- v1.20.7-
v1.19.11- v1.18.19*Mitigation
*To mitigate this vulnerability without upgrading kube-apiserver, you can
create a validating admission webhook that prevents EndpointSlices with
endpoint addresses in the 127.0.0.0/8 <http://127.0.0.0/8> and
169.254.0.0/16 <http://169.254.0.0/16> ranges. If you have an existing
admission policy mechanism (like OPA Gatekeeper) you can create a policy
that enforces this restriction.*Detection
*To detect whether this vulnerability has been exploited, you can list
EndpointSlices and check for endpoint addresses in the 127.0.0.0/8
<http://127.0.0.0/8> and 169.254.0.0/16 <http://169.254.0.0/16> ranges. If
you find evidence that this vulnerability has been exploited, please
contact security@...ernetes.io <security@...ernetes.io>*Additional Details
See Kubernetes Issue #102106
<https://github.com/kubernetes/kubernetes/issues/102106> for more details.
Acknowledgements
This vulnerability was reported by John Howard of Google.
Thank You,
CJ Cullen on behalf of the Kubernetes Product Security Committee
Powered by blists - more mailing lists
Please check out the
Open Source Software Security Wiki, which is counterpart to this
mailing list.
Confused about mailing lists and their use?
Read about mailing lists on Wikipedia
and check out these
guidelines on proper formatting of your messages.
