Denial of Service (DoS)

Affecting github.com/kubernetes/kubernetes/kubelet package, versions >=1.1.0 <1.16.13 || >=1.17.0 <1.17.9 || >=1.18.0 <1.18.6

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Overview

github.com/kubernetes/kubernetes/kubelet is an open source system for managing containerized applications across multiple hosts. It provides basic mechanisms for deployment, maintenance, and scaling of applications.

Affected versions of this package are vulnerable to Denial of Service (DoS). The Kubernetes kubelet component does not account for disk usage by a pod which writes to its own /etc/hosts file. The /etc/hosts file mounted in a pod by kubelet is not included by the kubelet eviction manager when calculating ephemeral storage usage by a pod. If a pod writes a large amount of data to the /etc/hosts file, it could fill the storage space of the node and cause the node to fail.

Details

Denial of Service (DoS) describes a family of attacks, all aimed at making a system inaccessible to its intended and legitimate users.

Unlike other vulnerabilities, DoS attacks usually do not aim at breaching security. Rather, they are focused on making websites and services unavailable to genuine users resulting in downtime.

One popular Denial of Service vulnerability is DDoS (a Distributed Denial of Service), an attack that attempts to clog network pipes to the system by generating a large volume of traffic from many machines.

When it comes to open source libraries, DoS vulnerabilities allow attackers to trigger such a crash or crippling of the service by using a flaw either in the application code or from the use of open source libraries.

Two common types of DoS vulnerabilities:

  • High CPU/Memory Consumption- An attacker sending crafted requests that could cause the system to take a disproportionate amount of time to process. For example, commons-fileupload:commons-fileupload.

  • Crash - An attacker sending crafted requests that could cause the system to crash. For Example, npm ws package

Remediation

Upgrade github.com/kubernetes/kubernetes/kubelet to version 1.16.13, 1.17.9, 1.18.6 or higher.

References

CVSS Score

5.5
medium severity
  • Attack Vector
    Local
  • Attack Complexity
    Low
  • Privileges Required
    Low
  • User Interaction
    None
  • Scope
    Unchanged
  • Confidentiality
    None
  • Integrity
    None
  • Availability
    High
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H/RL:O/RC:C
Credit
Unknown
CVE
CVE-2020-8557
CWE
CWE-400
Snyk ID
SNYK-GOLANG-GITHUBCOMKUBERNETESKUBERNETESKUBELET-590092
Disclosed
24 Jul, 2020
Published
24 Jul, 2020