CVE-2022-36103 Talos worker join token can be used to get elevated access level to the Talos API
Attackers with access to worker node machine configuration can use the join token to gain full control plane API access, potentially compromising the entire cluster.
- Exploited in the wild
- Not known
- Login needed
- An administrator
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2022-36103?
CVE-2022-36103 is a high-severity vulnerability in siderolabs talos, published on 13 Sep 2022. An attacker needs administrator access to exploit it, with no action from the victim.
Official description
Talos Linux is a Linux distribution built for Kubernetes deployments. Talos worker nodes use a join token to get accepted into the Talos cluster. Due to improper validation of the request while signing a worker node CSR (certificate signing request) Talos control plane node might issue Talos API certificate which allows full access to Talos API on a control plane node. Accessing Talos API with full level access on a control plane node might reveal sensitive information which allows full level access to the cluster (Kubernetes and Talos PKI, etc.). Talos API join token is stored in the machine configuration on the worker node. When configured correctly, Kubernetes workloads don't have access to the machine configuration, but due to a misconfiguration workload might access the machine configuration and reveal the join token. This problem has been fixed in Talos 1.2.2. Enabling the Pod Security Standards mitigates the vulnerability by denying hostPath mounts and host networking by default in the baseline policy. Clusters that don't run untrusted workloads are not affected. Clusters with correct Pod Security configurations which don't allow hostPath mounts, and secure access to cloud metadata server (or machine configuration is not supplied via cloud metadata server) are not affected.
Which versions are affected by CVE-2022-36103?
3 open source packages ship an affected version, including github.com/talos-systems/talos. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
github.com/talos-systems/talos Go | All versions | 1.2.2 |
github.com/talos-systems/talos Go | All versions | 1.2.2 |
github.com/talos-systems/talos Go | All versions | 1.2.2 |
Products include Siderolabs Talos Linux.
How do I fix CVE-2022-36103?
Upgrade github.com/talos-systems/talos to 1.2.2 or later.
Is CVE-2022-36103 being exploited?
There is no known exploitation of CVE-2022-36103 in the wild and no public exploit code.
Sources
Also known as GHSA-7hgc-php5-77qq, GO-2022-0995.