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GHSA-6r4j-4rjc-8vw5
No affected components available
Summary
Using an "open at the top" range definition in RBAC for etcd roles leads to some TCPs API servers being able to read, write and delete the data of other control planes.
Details
The problematic code is this: https://github.com/clastix/kamaji/blob/8cdc6191242f80d120c46b166e2102d27568225a/internal/datastore/etcd.go#L19-L24
The range created by this RBAC setup code looks like this:
etcdctl role get example
Role example
KV Read:
[/example/, \0)
KV Write:
[/example/, \0)
The range end \0 means "everything that comes after" in etcd, so potentially all the key prefixes of controlplanes with a name that comes after "example" when sorting lexically (e.g. example1, examplf, all the way to zzzzzzz if you will).
PoC
- Create two TCP in the same Namespace
- Scale Kamaji to zero to avoid reconciliations
- change the Kubernetes API Server
--etcd-prefixflag value to point to the other TCP datastore key - wait it for get it up and running
- use
kubectland will notice you're reading and writing data of another Tenant
Impact
Full control over other TCPs data, if you are able to obtain the name of other TCPs that use the same datastore and are able to obtain the user certificates used by your control plane (or you are able to configure the kube-apiserver Deployment, as shown in the PoC).
The vulnerability can be exploited over the network without needing physical access. It is easy for an attacker to exploit this vulnerability. An attacker needs basic access or low-level privileges. No user interaction is needed for the attacker to exploit this vulnerability. The impact is confined to the system where the vulnerability exists. There is a high impact on the confidentiality of the information. There is a high impact on the integrity of the data.
Exploitation activity has been observed. Apply available patches or mitigations urgently.
The exploit probability is very low. The vulnerability is unlikely to be exploited in the next 30 days.
We did not find any exploit available. Neither in GitHub repositories nor in the Exploit-Database.
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