#VU54814 Improper Authentication in VMware ESXi - CVE-2021-21994

Vulnerability identifier: #VU54814

Vulnerability risk: High

CVSSv4.0: 6.8 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:L/VA:L/SC:N/SI:N/SA:N/E:U/U:Amber]

CVE-ID: CVE-2021-21994

CWE-ID: CWE-287

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
VMware ESXi
Operating systems & Components / Operating system

Vendor: VMware, Inc

Description

The vulnerability allows a remote attacker to bypass authentication process.

The vulnerability exists due to an error in when processing authentication requests in SFCB (Small Footprint CIM Broker). A remote attacker can send specially crafted requests to port 5989/tcp, bypass SFCB authentication and gain unauthorized access to the system.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

VMware ESXi: ESXi_7.0.0-1.20.16321839 - 7.0

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External links
https://www.vmware.com/security/advisories/VMSA-2021-0014.html

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Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

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