Authentication bypass in QEMU

1) Improper Verification of Cryptographic Signature

EUVDB-ID: #VU28198

Risk: Low

CVSSv3.1: 3.9 [CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N/E:U/RL:O/RC:C]

CVE-ID: CVE-2020-10702

CWE-ID: CWE-347 - Improper Verification of Cryptographic Signature

Exploit availability: No

Description

The vulnerability allows a local user to bypass authentication.

The vulnerability exists due to usage of a weak signature algorithm within the /arm/pauth_helper.c in Pointer Authentication support for ARM. A local user can bypass PAuth and gain unauthorized access to resources on the system.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

QEMU: 4.0.0 - 4.2.0

External links

http://usn.ubuntu.com/4372-1/
http://security-tracker.debian.org/tracker/CVE-2020-10702
http://bugs.launchpad.net/qemu/+bug/1859713
http://git.qemu.org/?p=qemu.git;a=commit;h=de0b1bae6461f67243282555475f88b2384a1eb9

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.