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A malicious disk image could read a single file on the host filesystem as a qcow2/vmdk backing file

Low
AkihiroSuda published GHSA-f7qw-jj9c-rpq9 May 30, 2023

Package

lima (Homebrew)

Affected versions

< 0.16.0

Patched versions

0.16.0

Description

Note

The official templates of Lima, and the well-known third party products (Colima, Rancher Desktop, and Finch) are unlikely to be affected by this issue.

Impact

A virtual machine instance with a malicious disk image could read a single file on the host filesystem, even when no filesystem is mounted from the host.

To exploit this issue, the attacker has to embed the target file path (an absolute or a relative path from the instance directory) in a malicious disk image, as the qcow2 (or vmdk) backing file path string.
As Lima refuses to run as the root, it is practically impossible for the attacker to read the entire host disk via /dev/rdiskN.
Also, practically, the attacker cannot read at least the first 512 bytes (MBR) of the target file.

Patches

Patched in Lima v0.16.0, by prohibiting using a backing file path in the VM base image.

Workarounds

Do not use an untrusted disk image.

Severity

Low

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Local
Attack complexity
High
Privileges required
None
User interaction
Required
Scope
Changed
Confidentiality
Low
Integrity
None
Availability
None

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:C/C:L/I:N/A:N

CVE ID

CVE-2023-32684

Weaknesses

No CWEs