CVE-2020-27836
Description
A flaw was found in cluster-ingress-operator. A change to how the router-default service allows only certain IP source ranges could allow an attacker to access resources that would otherwise be restricted to specified IP ranges. The highest threat from this vulnerability is to data confidentiality and integrity as well as system availability.
Mitigation
Move the allowed IP source ranges from the loadBalancerSourceRanges setting to "service.beta.kubernetes.io/load-balancer-source-ranges" annotation. For example:
oc -n openshift-ingress annotate svc/router-default service.beta.kubernetes.io/load-balancer-source-ranges=10.0.0.0/8,192.168.0.0/16
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 | 7.5 | 9.8 | N/A |
| Attack Vector | Network | Network | N/A |
| Attack Complexity | High | Low | N/A |
| Privileges Required | Low | 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:L/UI:N/S:U/C:H/I:H/A:H
NVD: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Red Hat CVSS v3 Score Explanation
This vulnerability can only be triggered during a cluster upgrade, so exploitation of a significant unrelated vulnerability or direct access to the OpenShift environment would already be required.
Understanding the Weakness (CWE)
Confidentiality
Technical Impact: Read Application Data; Read Files or Directories
An attacker may be able to read sensitive information from the associated resource, such as credentials or configuration information stored in a file.
Access Control
Technical Impact: Gain Privileges or Assume Identity
An attacker may be able to modify critical properties of the associated resource to gain privileges, such as replacing a world-writable executable with a Trojan horse.
Integrity,Other
Technical Impact: Modify Application Data; Other
An attacker may be able to destroy or corrupt critical data in the associated resource, such as deletion of records from a database.
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