CVE-2020-8555
Description
A server side request forgery (SSRF) flaw was found in Kubernetes. The kube-controller-manager allows authorized users with the ability to create StorageClasses or certain Volume types to leak up to 500 bytes of arbitrary information from the master's host network. This can include secrets from the kube-apiserver through the unauthenticated localhost port (if enabled).
Statement
OpenShift Container Platform does not expose kube-apiserver through an unauthenticated localhost port. However, other link-local addresses are reachable without authentication that allow an attacker to access sensitive data.
The version of heketi shipped with Red Hat Gluster Storage 3 includes the affected client side code for heketi and quobyte volume plugin, however the vulnerable functionality is currently not used by the product and hence this issue has been rated as having a security impact of Low.
Red Hat Openshift Container Storage 4.2 is not affected by this vulnerability as rook-ceph-operator container does not include support for affected volume plugins(storageos, scaleio, glusterfs, quobyte).
Mitigation
Restrict use of the vulnerable volume type and restrict StorageClass write permissions via RBAC
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 6.3 | 6.3 | N/A |
| Attack Vector | Network | Network | N/A |
| Attack Complexity | High | High | N/A |
| Privileges Required | Low | Low | N/A |
| User Interaction | None | None | N/A |
| Scope | Changed | Changed | N/A |
| Confidentiality | High | High | N/A |
| Integrity Impact | None | None | N/A |
| Availability Impact | None | None | N/A |
Vector
Red Hat: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:N/A:N
NVD: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:N/A:N
Understanding the Weakness (CWE)
Confidentiality
Technical Impact: Read Application Data
Acknowledgements
Red Hat would like to thank the Kubernetes Product Security Committee for reporting this issue. Upstream acknowledges Brice Augras (Groupe-Asten) and Christophe Hauquiert (Nokia) as the original reporters.
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