Authentication bypass in VMware Tools

1) Improper Authentication

EUVDB-ID: #VU77208

Risk: High

CVSSv3.1: 7.8 [CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H/E:H/RL:O/RC:C]

CVE-ID: CVE-2023-20867

CWE-ID: CWE-287 - Improper Authentication

Exploit availability: No

Description

The vulnerability allows a remote attacker to bypass authentication process.

The vulnerability exists due to an error in the vgauth module. An attacker who compromised the ESXi host can bypass authentication process and execute privileged commands across Windows, Linux, and PhotonOS (vCenter) guest VMs without authentication of guest credentials from a compromised ESXi host and no default logging on guest VMs.

Note, the vulnerability is being actively exploited in the wild by the UNC3886 APT actor.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

VMware Tools: 10.0.0 - 12.2.0

External links

http://www.vmware.com/security/advisories/VMSA-2023-0013.html
http://www.mandiant.com/resources/blog/vmware-esxi-zero-day-bypass

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.

Is there known malware, which exploits this vulnerability?

Yes. This vulnerability is being exploited in the wild.