Quantum Secular Labs / Blog / Advisories

CVE-2017-1002101: Kubernetes: Improper Link Resolution Before File Access

CVE-2017-1002101 is rated critical with a CVSS v3.0 base score of 9.6 and affects Kubernetes. Per its scoring, it can be exploited over the network, without any user interaction.

Vulnerability description

In Kubernetes versions 1.3.x, 1.4.x, 1.5.x, 1.6.x and prior to versions 1.7.14, 1.8.9 and 1.9.4 containers using subpath volume mounts with any volume type (including non-privileged pods, subject to file permissions) can access files/directories outside of the volume, including the host's filesystem.

Severity breakdown

CVSS v3.0 9.6: CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:N

  • Attack vector: Network. Exploitable remotely over the network, with no need for local or physical access.
  • Attack complexity: Low. No special conditions; the attack can be repeated reliably.
  • Privileges required: Low. A basic user account is enough.
  • User interaction: None. No action from any user is needed.
  • Scope: Changed. Impact reaches beyond the vulnerable component to other resources.
  • Confidentiality impact: High. Total loss of confidentiality; sensitive data can be fully disclosed.
  • Integrity impact: High. Total loss of integrity; data or system state can be fully modified.
  • Availability impact: None. No effect on availability.

Underlying weakness

CWE-59: Improper Link Resolution Before File Access

The product attempts to access a file based on the filename, but it does not properly prevent that filename from identifying a link or shortcut that resolves to an unintended resource.

Affected products

  • Kubernetes: from 1.3.0 up to and including 1.3.10; from 1.4.0 up to and including 1.4.12; from 1.5.0 up to and including 1.5.8; from 1.6.0 up to and including 1.6.13; from 1.7.0 before 1.7.14; from 1.8.0 before 1.8.9; from 1.9.0 before 1.9.4

References