Denial of service in flux controllers in github.com/fluxcd modules

2022-10-2816:07:05

Google

osv.dev

flux controllers

denial of service

vulnerability

github.com/fluxcd

invalid data

object processing

permissions

validation issue

kubernetes

timeout

github issue

CVSS3

Attack Vector

NETWORK

Attack Complexity

LOW

Privileges Required

LOW

User Interaction

NONE

Scope

CHANGED

Confidentiality Impact

NONE

Integrity Impact

NONE

Availability Impact

LOW

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:L

AI Score

4.4

Confidence

High

EPSS

0.001

Percentile

32.8%

JSON

Flux controllers are vulnerable to a denial of service attack.

Users that have permissions to change Flux’s objects, either through a Flux source or directly within a cluster, can provide invalid data to fields .spec.interval or .spec.timeout (and structured variations of these fields), causing the entire object type to stop being processed.

The issue has two root causes: a) the Kubernetes type metav1.Duration is not fully compatible with the Go type time.Duration as explained in https://github.com/kubernetes/apimachinery/issues/131, and b) a lack of validation within Flux to restrict allowed values.