Attacker Value
Very Low
(1 user assessed)
Exploitability
Very Low
(1 user assessed)
User Interaction
None
Privileges Required
None
Attack Vector
Network
0

Kubectl/API Server YAML parsing vulnerable to "Billion Laughs" Attack

Disclosure Date: October 17, 2019
Add MITRE ATT&CK tactics and techniques that apply to this CVE.

Description

Improper input validation in the Kubernetes API server in versions v1.0-1.12 and versions prior to v1.13.12, v1.14.8, v1.15.5, and v1.16.2 allows authorized users to send malicious YAML or JSON payloads, causing the API server to consume excessive CPU or memory, potentially crashing and becoming unavailable. Prior to v1.14.0, default RBAC policy authorized anonymous users to submit requests that could trigger this vulnerability. Clusters upgraded from a version prior to v1.14.0 keep the more permissive policy by default for backwards compatibility.

Add Assessment

2
Ratings
  • Attacker Value
    Very Low
  • Exploitability
    Very Low
Technical Analysis

As I understand it, most kubernetes clusters will require auth or a foothold to reach in the first place. Why would you bother with a DoS attack at that point? Much more attacker value to be had in exploiting the cluster in ways that don’t bring it down.

Compare authenticated:
https://www.shodan.io/search?query=kubernetes+401

And unauthenticated searches:
https://www.shodan.io/search?query=kubernetes+%21401

CVSS V3 Severity and Metrics
Base Score:
7.5 High
Impact Score:
3.6
Exploitability Score:
3.9
Vector:
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Attack Vector (AV):
Network
Attack Complexity (AC):
Low
Privileges Required (PR):
None
User Interaction (UI):
None
Scope (S):
Unchanged
Confidentiality (C):
None
Integrity (I):
None
Availability (A):
High

General Information

Vendors

  • kubernetes,
  • redhat

Products

  • kubernetes,
  • openshift container platform 3.10,
  • openshift container platform 3.11,
  • openshift container platform 3.9
Technical Analysis