CVE-2021-27851

Description


A security vulnerability that can lead to local privilege escalation has been found in ’guix-daemon’. It affects multi-user setups in which ’guix-daemon’ runs locally. The attack consists in having an unprivileged user spawn a build process, for instance with `guix build`, that makes its build directory world-writable. The user then creates a hardlink to a root-owned file such as /etc/shadow in that build directory. If the user passed the --keep-failed option and the build eventually fails, the daemon changes ownership of the whole build tree, including the hardlink, to the user. At that point, the user has write access to the target file. Versions after and including v0.11.0-3298-g2608e40988, and versions prior to v1.2.0-75109-g94f0312546 are vulnerable.

Related CPE's


References


PatchVendor Advisory

Issue TrackingMailing ListPatchVendor Advisory

CvssV3 impact


BaseSeverity

MEDIUM

ConfidentialityImpact

NONE

AttackComplexity

LOW

Scope

UNCHANGED

AttackVector

LOCAL

AvailabilityImpact

NONE

IntegrityImpact

HIGH

PrivilegesRequired

LOW

BaseScore

5.5

VectorString

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N

Version

3.1

UserInteraction

NONE

CvssV2 impact


AccessComplexity

LOW

ConfidentialityImpact

NONE

AvailabilityImpact

NONE

IntegrityImpact

PARTIAL

BaseScore

2.1

VectorString

AV:L/AC:L/Au:N/C:N/I:P/A:N

Version

2.0

AccessVector

LOCAL

Authentication

NONE