CVE-2021-21985 VMware vCenter Server: web page flaw
In plain words: A web app can be made to act on someone's behalf or reach places it should not. Stolen sessions, actions taken as the victim, or access to internal systems.
Confirmed exploited by CISA on · US federal patch deadline Nov 17, 2021
What to do
- Install VMware's security update for vCenter Server. If no update exists, follow the vendor's workaround or stop using the product until one ships.
- Keep a list of every internet-facing server you run so nothing is forgotten.
- Patch anything in this catalog first, ahead of normal patch cycles.
- Put admin and file-transfer apps behind a VPN or single sign-on instead of the open internet.
Who is affected
Work IT. Aimed mostly at company systems — you are affected through the companies you use, not your own phone.
What's at risk: Mass data theft and ransomware: a single flaw in a file-transfer or email server has exposed thousands of organisations at once.
The details
- Official name
- VMware vCenter Server Improper Input Validation Vulnerability
- Product
- VMware vCenter Server
- CISA description
- VMware vSphere Client contains an improper input validation vulnerability in the Virtual SAN Health Check plug-in, which is enabled by default in vCenter Server, which allows for remote code execution.
- Type of flaw
- Web page flaw (CWE-20, CWE-470, CWE-918)
- Confirmed exploited
- Nov 3, 2021 — known to be used in ransomware attacks
- US federal patch deadline
- Nov 17, 2021
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Answering about CVE-2021-21985 ·
Questions about CVE-2021-21985
Is CVE-2021-21985 being exploited?
Yes. CISA added CVE-2021-21985 to its Known Exploited Vulnerabilities catalog on Nov 3, 2021, which means there is reliable evidence of real-world attacks, including by ransomware groups.
How do I fix CVE-2021-21985?
Install VMware's security update for vCenter Server. If no update exists, follow the vendor's workaround or stop using the product until one ships. Keep a list of every internet-facing server you run so nothing is forgotten.
Am I affected by CVE-2021-21985?
Only if you use VMware vCenter Server. Aimed mostly at company systems — you are affected through the companies you use, not your own phone.