GHSA-cvx8-ppmc-78hm

Описание

Duplicate Advisory

This advisory is a duplicate of GHSA-qv98-3369-g364. This link is maintained to preserve external references.

Original Description

Summary As part of a Kubevirt audit performed by NCC group, a finding dealing with systemic lack of path sanitization which leads to a path traversal was identified. Google tested the exploitability of the paths in the audit report and identified that when combined with another vulnerability one of the paths leads to an arbitrary file read on the host from the VM.

The read operations are limited to files which are publicly readable or which are readable for UID 107 or GID 107. /proc/self/<> is not accessible.

Severity

Moderate - The vulnerability is proven to exist in an open source version of KubeVirt by NCC Group while being combined with Systemic Lack of Path Sanitization, which leads to Path traversal.

Proof of Concept

The initial VMI specifications can be written as such to reproduce the issue:

The VMI can then be started through kubectl apply -f vm-test-ncc.yaml. The requested file is accessible once the VM is up and can be accessed under /dev/vdc.

Depending on the environment, path may contain more or less /.., something that can easily be tested by checking the events until the VMI can start without failure. Restrictions

SELinux may mitigate this vulnerability.

When using a node with selinux, selinux denies the access and the VM start was aborted:

After making selinux permissive the VM can boot and access /etc/passwd from the node within the guest:

Further Analysis In order to mitigate this vulnerability, Sanitize imagePath in pkg/container-disk/container-disk.go following ISE best practices described and Add checks in pkg/virt-api/webhooks/validating-webhook/admitters/vmi-create-admitter.go

Timeline Date reported: 05/10/2022 Date fixed: N/A Date disclosed: 08/08/2022