Headline
CVE-2023-27486: Insufficient authorization validation between zones when xCAT zones are enabled
xCAT is a toolkit for deployment and administration of computer clusters. In versions prior to 2.16.5 if zones are configured as a mechanism to secure clusters in XCAT, it is possible for a local root user from one node to obtain credentials to SSH to any node in any zone, except the management node of the default zone. XCAT zones are not enabled by default. Only users that use the optional zone feature are impacted. All versions of xCAT prior to xCAT 2.16.5 are vulnerable. This problem has been fixed in xCAT 2.16.5. Users making use of zones should upgrade to 2.16.5. Users unable to upgrade may mitigate the issue by disabling zones or patching the management node with the fix contained in commit 85149c37f49.
The xCAT zones feature can be used to divide groups of nodes in the cluster into multiple zones that have independent ssh keys. xCAT zones are optional and not enabled by default. If zones are configured in xCAT, it is possible for a root user from one node to obtain ssh keys from other zones and SSH to any node in any zone, breaking the zone enforcement.
Impact
Only users that use the optional zones feature are impacted. All versions of xCAT prior to xCAT 2.16.5 are vulnerable.
Patches
The issue has been fixed in xCAT 2.16.5. Users making use of zones should upgrade to xCAT 2.16.5.
Workarounds
The problem can be worked around by disabling zones or patching the management node with the fix contained in #7247.
Acknowledgement
We would like to thank Dr. Stefan Albensoeder (Enercon) for reporting this issue, as well as contributing to the fix.
References
#7246
#7247