CVE-2020-8558: K8s.io/kubernetes Improper Authentication Vulnerability
HIGHCVE-2020-8558 is a HIGH (CVSS 8.8) improper authentication vulnerability (CWE-420: Unprotected Alternate Channel) affecting K8s.io/kubernetes libraries in the Go ecosystem. The issue involves improper authentication in kubernetes. Remediation is available by upgrading affected packages to version 1.18.4, 1.17.7, 1.16.11.
CVE-2020-8558 at a Glance
Security Impact
CVSS: 8.8
The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H).
How to Fix CVE-2020-8558
To remediate this vulnerability, upgrade all affected K8s.io/kubernetes dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.
Upgrade k8s.io/kubernetes to 1.18.4Upgrade k8s.io/kubernetes to 1.17.7Upgrade k8s.io/kubernetes to 1.16.11Run the following command in your project directory to verify that all resolved dependencies use the patched release:
inspect dependencies for k8s.io/kubernetesHow to Check if You Are Affected
To determine whether your application is affected by CVE-2020-8558, inspect your project dependencies for K8s.io/kubernetes:
inspect dependencies for k8s.io/kubernetesAnalyze the terminal output to locate any version of K8s.io/kubernetes in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 1.18.4), your application is affected.
Note: Verify declared build manifests and deployed runtime container environments.
Technical Details
Vulnerability Mechanism & Technical Analysis
This vulnerability is classified under CWE-420: Unprotected Alternate Channel, where the product protects a primary channel, but it does not use the same level of protection for an alternate channel. In K8s.io/kubernetes, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.
Source Advisory Statement
CVE-2020-8558 Affected K8s.io/kubernetes Versions
3 component(s)| Product / Package | Ecosystem | Affected Versions | Fixed Version |
|---|---|---|---|
|
k8s.io/kubernetes
|
Go |
≥ 1.18.0
< 1.18.4
|
1.18.4
|
|
k8s.io/kubernetes
|
Go |
≥ 1.17.0
< 1.17.7
|
1.17.7
|
|
k8s.io/kubernetes
|
Go |
< 1.16.11
|
1.16.11
|
References
Frequently Asked Questions
What is CVE-2020-8558?
Which K8s.io/kubernetes versions are affected?
What version fixes CVE-2020-8558?
Is k8s.io/kubernetes affected?
What is the CVSS score of CVE-2020-8558?
What CWE is associated with CVE-2020-8558?
How can I check Go dependencies for CVE-2020-8558?
Machine-readable OSV JSON
OSV v1.5 Schema
{
"schema_version" : "1.4.0",
"id" : "GHSA-wqv3-8cm6-h6wg",
"modified" : "2023-01-06T22:23:41Z",
"published" : "2022-02-15T01:57:18Z",
"aliases" : [ "CVE-2020-8558" ],
"summary" : "Improper Authentication in Kubernetes",
"details" : "A security issue was discovered in the Kubelet and kube-proxy components of Kubernetes which allows adjacent hosts to reach TCP and UDP services bound to 127.0.0.1 running on the node or in the node's network namespace. For example, if a cluster administrator runs a TCP service on a node that listens on 127.0.0.1:1234, because of this bug, that service would be potentially reachable by other hosts on the same LAN as the node, or by containers running on the same node as the service. If the example service on port 1234 required no additional authentication (because it assumed that only other localhost processes could reach it), then it could be vulnerable to attacks that make use of this bug.",
"severity" : [ {
"type" : "CVSS_V3",
"score" : "CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"
} ],
"affected" : [ {
"package" : {
"ecosystem" : "Go",
"name" : "k8s.io/kubernetes"
},
"ranges" : [ {
"type" : "ECOSYSTEM",
"events" : [ {
"introduced" : "1.18.0"
}, {
"fixed" : "1.18.4"
} ]
} ]
}, {
"package" : {
"ecosystem" : "Go",
"name" : "k8s.io/kubernetes"
},
"ranges" : [ {
"type" : "ECOSYSTEM",
"events" : [ {
"introduced" : "1.17.0"
}, {
"fixed" : "1.17.7"
} ]
} ]
}, {
"package" : {
"ecosystem" : "Go",
"name" : "k8s.io/kubernetes"
},
"ranges" : [ {
"type" : "ECOSYSTEM",
"events" : [ {
"introduced" : "0"
}, {
"fixed" : "1.16.11"
} ]
} ]
} ],
"references" : [ {
"type" : "WEB",
"url" : "https://github.com/bottlerocket-os/bottlerocket/security/advisories/GHSA-wqv3-8cm6-h6wg"
}, {
"type" : "ADVISORY",
"url" : "https://nvd.nist.gov/vuln/detail/CVE-2020-8558"
}, {
"type" : "WEB",
"url" : "https://github.com/kubernetes/kubernetes/issues/92315"
}, {
"type" : "WEB",
"url" : "https://bugzilla.redhat.com/show_bug.cgi?id=1843358"
}, {
"type" : "WEB",
"url" : "https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-8558"
}, {
"type" : "PACKAGE",
"url" : "https://github.com/kubernetes/kubernetes"
}, {
"type" : "WEB",
"url" : "https://github.com/tabbysable/POC-2020-8558"
}, {
"type" : "WEB",
"url" : "https://groups.google.com/g/kubernetes-announce/c/sI4KmlH3S2I/m/TljjxOBvBQAJ"
}, {
"type" : "WEB",
"url" : "https://groups.google.com/g/kubernetes-security-announce/c/B1VegbBDMTE"
}, {
"type" : "WEB",
"url" : "https://labs.bishopfox.com/tech-blog/bad-pods-kubernetes-pod-privilege-escalation"
}, {
"type" : "WEB",
"url" : "https://security.netapp.com/advisory/ntap-20200821-0001"
}, {
"type" : "WEB",
"url" : "https://www.openwall.com/lists/oss-security/2020/07/08/1"
} ],
"database_specific" : {
"cwe_ids" : [ "CWE-420" ],
"severity" : "HIGH",
"github_reviewed" : true,
"github_reviewed_at" : "2021-05-24T19:30:36Z",
"nvd_published_at" : "2020-07-27T20:15:00Z"
}
}