CVE-2024-43803 BMO can expose particularly named secrets from other namespaces via BMH CRD
An attacker with BMH creation rights can exfiltrate secrets from other namespaces by referencing them in host provisioning data.
- Exploited in the wild
- Not known
- Login needed
- An administrator
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2024-43803?
CVE-2024-43803 is a medium-severity missing authorization vulnerability in metal3-io baremetal-operator, published on 3 Sep 2024. An attacker needs administrator access to exploit it, with no action from the victim.
Official description
The Bare Metal Operator (BMO) implements a Kubernetes API for managing bare metal hosts in Metal3. The `BareMetalHost` (BMH) CRD allows the `userData`, `metaData`, and `networkData` for the provisioned host to be specified as links to Kubernetes Secrets. There are fields for both the `Name` and `Namespace` of the Secret, meaning that versions of the baremetal-operator prior to 0.8.0, 0.6.2, and 0.5.2 will read a `Secret` from any namespace. A user with access to create or edit a `BareMetalHost` can thus exfiltrate a `Secret` from another namespace by using it as e.g. the `userData` for provisioning some host (note that this need not be a real host, it could be a VM somewhere).
BMO will only read a key with the name `value` (or `userData`, `metaData`, or `networkData`), so that limits the exposure somewhat. `value` is probably a pretty common key though. Secrets used by _other_ `BareMetalHost`s in different namespaces are always vulnerable. It is probably relatively unusual for anyone other than cluster administrators to have RBAC access to create/edit a `BareMetalHost`. This vulnerability is only meaningful, if the cluster has users other than administrators and users' privileges are limited to their respective namespaces.
The patch prevents BMO from accepting links to Secrets from other namespaces as BMH input. Any BMH configuration is only read from the same namespace only. The problem is patched in BMO releases v0.7.0, v0.6.2 and v0.5.2 and users should upgrade to those versions. Prior upgrading, duplicate the BMC Secrets to the namespace where the corresponding BMH is. After upgrade, remove the old Secrets. As a workaround, an operator can configure BMO RBAC to be namespace scoped for Secrets, instead of cluster scoped, to prevent BMO from accessing Secrets from other namespaces.
Which versions are affected by CVE-2024-43803?
7 open source packages ship an affected version, including github.com/metal3-io/baremetal-operator.
| Package | Affected | Fixed in |
|---|---|---|
github.com/metal3-io/baremetal-operator Go | All versions | 0.5.2, 0.6.2, 0.8.0 |
github.com/metal3-io/baremetal-operator Go | All versions | 0.5.2 |
github.com/metal3-io/baremetal-operator Go | All versions | 0.5.2 |
github.com/metal3-io/baremetal-operator Go | From 0.6.0 | 0.6.2 |
github.com/metal3-io/baremetal-operator Go | From 0.6.0 | 0.6.2 |
github.com/metal3-io/baremetal-operator Go | From 0.7.0-rc.0 | 0.8.0 |
1 more packages
github.com/metal3-io/baremetal-operator Go | From 0.7.0-rc.0 | 0.8.0 |
How do I fix CVE-2024-43803?
Upgrade github.com/metal3-io/baremetal-operator to a fixed version for your release line: 0.5.2, 0.6.2 or 0.8.0.
Upgrade, and check permissions on every request on the server, not only in the interface. More about Missing authorization.
Is CVE-2024-43803 being exploited?
There is no known exploitation of CVE-2024-43803 in the wild and no public exploit code.
Sources
Also known as GHSA-pqfh-xh7w-7h3p, GO-2024-3109.