Impact
An attacker with the ability to create or modify CiliumNetworkPolicy objects in a particular namespace is able to affect traffic on an entire Cilium cluster, potentially bypassing policy enforcement in other namespaces.
By using a crafted endpointSelector that uses the DoesNotExist operator on the reserved:init label, the attacker can create policies that bypass namespace restrictions and affect the entire Cilium cluster. This includes potentially allowing or denying all traffic.
This attack requires API server access, as described in the Kubernetes API Server Attacker section of the Cilium Threat Model.
Patches
This issue was patched in cilium/cilium#28007
This issue affects:
- Cilium <= v1.14.1
- Cilium <= v1.13.6
- Cilium <= v1.12.13
This issue has been resolved in:
- Cilium v1.14.2
- Cilium v1.13.7
- Cilium v1.12.14
Workarounds
An admission webhook can be used to prevent the use of endpointSelectors that use the DoesNotExist operator on the reserved:init label in CiliumNetworkPolicies.
Acknowledgements
The Cilium community has worked together with members of Palantir and Isovalent to prepare these mitigations. Special thanks to @odinuge for reporting this issue and @joestringer for the fix.
For more information
If you have any questions or comments about this advisory, please reach out on Slack.
If you think you have found a vulnerability in Cilium, we strongly encourage you to report it to our private security mailing list at [email protected] first, before disclosing it in any public forum. This is a private mailing list for Cilium's internal security team, and your report will be treated as top priority.
References
odinuge Reporter
Impact
An attacker with the ability to create or modify CiliumNetworkPolicy objects in a particular namespace is able to affect traffic on an entire Cilium cluster, potentially bypassing policy enforcement in other namespaces.
By using a crafted
endpointSelectorthat uses theDoesNotExistoperator on thereserved:initlabel, the attacker can create policies that bypass namespace restrictions and affect the entire Cilium cluster. This includes potentially allowing or denying all traffic.This attack requires API server access, as described in the Kubernetes API Server Attacker section of the Cilium Threat Model.
Patches
This issue was patched in cilium/cilium#28007
This issue affects:
This issue has been resolved in:
Workarounds
An admission webhook can be used to prevent the use of
endpointSelectors that use theDoesNotExistoperator on thereserved:initlabel in CiliumNetworkPolicies.Acknowledgements
The Cilium community has worked together with members of Palantir and Isovalent to prepare these mitigations. Special thanks to @odinuge for reporting this issue and @joestringer for the fix.
For more information
If you have any questions or comments about this advisory, please reach out on Slack.
If you think you have found a vulnerability in Cilium, we strongly encourage you to report it to our private security mailing list at [email protected] first, before disclosing it in any public forum. This is a private mailing list for Cilium's internal security team, and your report will be treated as top priority.
References