Privilege escalation in QEMU

1) Incorrect default permissions

EUVDB-ID: #VU61492

Risk: Low

CVSSv3.1: 6.2 [CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N/E:U/RL:O/RC:C]

CVE-ID: CVE-2022-0358

CWE-ID: CWE-276 - Incorrect Default Permissions

Exploit availability: No

Description

The vulnerability allows a local user to escalate privileges on the system.

The vulnerability exists due to incorrect QEMU virtio-fs shared file system daemon (virtiofsd) implementation. An attacker on the guest OS can create files in the directories shared by virtio-fs with unintended group ownership in a scenario where a directory is SGID to a certain group and is writable by a user who is not a member of the group. This can lead to privilege escalation within the guest OS.

The vulnerability exists due to incomplete fox for #VU13631 (CVE-2018-13405).

Mitigation

Install updates from vendor's website.

Vulnerable software versions

QEMU: All versions

External links

http://bugzilla.redhat.com/show_bug.cgi?id=2044863
http://lists.gnu.org/archive/html/qemu-devel/2022-01/msg05447.html

Q & A

Can this vulnerability be exploited remotely?

No. This vulnerability can be exploited locally. The attacker should have authentication credentials and successfully authenticate on the system.

How the attacker can exploit this vulnerability?

The attacker would have to trick the victim to open a a specially crafted file.

The attacker would have to login to the system and perform certain actions in order to exploit this vulnerability.

Is there known malware, which exploits this vulnerability?

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