CVE-2021-3917
coreos-installer < 0.10.0 writes world-readable Ignition config to installed system
Impact
### Impact On systems installed with coreos-installer before 0.10.0, the user-provided Ignition config was written to `/boot/ignition/config.ign` with world-readable permissions, granting unprivileged users access to any secrets included in the config. Default configurations of Fedora CoreOS and RHEL CoreOS do not include any unprivileged user accounts. In addition, instances launched from a cloud image, and systems provisioned with the `ignition.config.url` kernel argument, do not use the `config.ign` file and are unaffected. ### Patches coreos-installer 0.10.0 and later [writes](https://github.com/coreos/coreos-installer/pull/571) the Ignition config with restricted permissions. ### Workarounds On Fedora CoreOS systems installed from version 34.20210711.3.0 (stable), 34.20210711.2.0 (testing), 34.20210711.1.1 (next) and later, the `/boot/ignition` directory and its contents are removed after provisioning is complete. All Fedora CoreOS systems that have updated to these versions or later have automatically removed the `/boot/ignition` directory and no action is required. On other systems, `/boot/ignition/config.ign` can be removed manually, as it is not used after provisioning is complete: ``` sudo mount -o remount,rw /boot sudo rm -rf /boot/ignition ``` ### References For more information, see https://github.com/coreos/fedora-coreos-tracker/issues/889. ### For more information If you have any questions or comments about this advisory, [open an issue in coreos-installer](https://github.com/coreos/coreos-installer/issues/new/choose) or email the CoreOS [development mailing list](https://lists.fedoraproject.org/archives/list/coreos@lists.fedoraproject.org/).
Affected packages
| Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|
| rust | coreos-installer | < 0.10.0 | 0.10.0 |
Affected products
| Vendor | Product | Affected versions |
|---|---|---|
| Redhat | Coreos-Installer | before 0.10.0 |
Weakness classification
References
- NVD record
- CVE.org record
- GitHub advisory
- https://access.redhat.com/security/cve/CVE-2021-3917
- https://bugzilla.redhat.com/show_bug.cgi?id=2018478
- https://github.com/coreos/coreos-installer/commit/2a36405339c87b16ed6c76e91ad5b76638fbdb0c
- https://github.com/coreos/fedora-coreos-tracker/issues/889
- https://github.com/advisories/GHSA-862g-9h5m-m3qv
- https://github.com/coreos/coreos-installer/security/advisories/GHSA-862g-9h5m-m3qv
- https://github.com/coreos/coreos-installer/releases/tag/v0.10.0
- https://nvd.nist.gov/vuln/detail/CVE-2021-3917