CVE-2023-30840

On a compromised node, the fluid-csi service account can be used to modify node specs

Workarounds

Delete the csi-nodeplugin-fluid daemonset in fluid-system namespace and avoid using CSI mode to mount FUSE file systems. Alternatively using sidecar mode to mount FUSE file systems is recommended. Refer to the doc to get a full example of how to use sidecar mode.

References

Fixed by Fix rbacs and limit CSI Plugin's node related access

Credits

Special thanks to the discoverers of this issue:

Nanzi Yang ([email protected])

If a malicious user gains control of a Kubernetes node running fluid csi pod (controlled by the csi-nodeplugin-fluid node-daemonset), he/she can leverage the fluid-csi service account to modify specs of all the nodes in the cluster. However, since this service account lacks "list node" permissions, the attacker may need to use other techniques to identify vulnerable nodes.

Once the attacker identifies and modifies the node specs, he/she can manipulate system-level-privileged components to access all secrets in the cluster or execute pods on other nodes. This allows he/she to elevate privileges beyond the compromised node and potentially gain full privileged access to the whole cluster.

To exploit this vulnerability, the attacker can make all other nodes unschedulable (for example, patch node with taints) and wait for system-critical components with high privilege to appear on the compromised node. However, this attack requires two prerequisites: a compromised node and identifying all vulnerable nodes through other means. Additionally, since the attack is passive and requires patience and luck, the severity of this finding is considered medium.

The application does not correctly enforce access controls, allowing a principal to access resources or operations beyond their granted permissions. Typical impact: unauthorized data access or execution of privileged operations.

CVE-2023-30840 has a CVSS score of 4.0 (Medium). The vector is requires local access, high privileges required, and user interaction required. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (0.8.6); upgrading removes the vulnerable code path.

Kodem intelligence

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For users who're using version < 0.8.6, >= 0.7.0, upgrade to v0.8.6.

1. What is CVE-2023-30840? CVE-2023-30840 is a medium-severity incorrect authorization vulnerability in github.com/fluid-cloudnative/fluid (go), affecting versions >= 0.7.0, < 0.8.6. It is fixed in 0.8.6. The application does not correctly enforce access controls, allowing a principal to access resources or operations beyond their granted permissions.
2. How severe is CVE-2023-30840? CVE-2023-30840 has a CVSS score of 4.0 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which versions of github.com/fluid-cloudnative/fluid are affected by CVE-2023-30840? github.com/fluid-cloudnative/fluid (go) versions >= 0.7.0, < 0.8.6 is affected.
4. Is there a fix for CVE-2023-30840? Yes. CVE-2023-30840 is fixed in 0.8.6. Upgrade to this version or later.
5. Is CVE-2023-30840 exploitable, and should I be worried? Whether CVE-2023-30840 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
6. What actually determines whether CVE-2023-30840 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
7. How do I fix CVE-2023-30840? Upgrade github.com/fluid-cloudnative/fluid to 0.8.6 or later.

Other vulnerabilities in github.com/fluid-cloudnative/fluid