Security restrictions bypass in libvirt

1) Incorrect permission assignment for critical resource

EUVDB-ID: #VU62735

Risk: Medium

CVSSv3.1: 5.6 [CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N/E:U/RL:O/RC:C]

CVE-ID: CVE-2021-3631

CWE-ID: CWE-732 - Incorrect Permission Assignment for Critical Resource

Exploit availability: No

Description

The vulnerability allows a local user to gain access to sensitive information.

The vulnerability exists due to an error in the way SELinux MCS category pairs for VMs' dynamic labels in security/security_selinux.c. An attacker with access to the guest OS can access files labeled for another guest.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

libvirt: 5.10.0 - 7.4.0

External links

http://access.redhat.com/errata/RHSA-2021:3631
http://gitlab.com/libvirt/libvirt/-/commit/15073504dbb624d3f6c911e85557019d3620fdb2
http://bugzilla.redhat.com/show_bug.cgi?id=1977726
http://gitlab.com/libvirt/libvirt/-/issues/153
http://security.netapp.com/advisory/ntap-20220331-0010/

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote authenticated user via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.