CVE-2021-20198
Description
A flaw was found in the OpenShift Installer. During installation of OpenShift Container Platform 4 clusters, bootstrap nodes are provisioned with anonymous authentication enabled on kubelet port 10250. A remote attacker able to reach this port during installation can make unauthenticated /exec requests to execute arbitrary commands within running containers. The highest threat from this vulnerability is to data confidentiality and integrity as well as system availability.
Mitigation
This issue is mitigated by default on AWS, Azure, GCP and OpenStack as port 10250 is not remotely accessible on bootstrap nodes. For other IPI platforms, bootstrap nodes only exist during the installation window so the exposure is limited. For UPI installations, administrators should prevent remote access to this port on bootstrap nodes and/or remove the nodes once installation is complete
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 | 8.1 | 8.1 | N/A |
| Attack Vector | Network | Network | N/A |
| Attack Complexity | High | High | N/A |
| Privileges Required | None | None | N/A |
| User Interaction | None | None | N/A |
| Scope | Unchanged | Unchanged | N/A |
| Confidentiality | High | High | N/A |
| Integrity Impact | High | High | N/A |
| Availability Impact | High | High | N/A |
Vector
Red Hat: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
NVD: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
Understanding the Weakness (CWE)
Access Control,Other
Technical Impact: Gain Privileges or Assume Identity; Varies by Context
Exposing critical functionality essentially provides an attacker with the privilege level of that functionality. The consequences will depend on the associated functionality, but they can range from reading or modifying sensitive data, accessing administrative or other privileged functionality, or possibly even executing arbitrary code.
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