The BSI warns of a massive global attack wave on VMware ESXi systems using the known vulnerability CVE-2021-21974. The vulnerability has been known since February 2021 and has been closed by a patch.
If you are running such a system, please read the attached document carefully and apply the patch immediately if necessary.
Update:
As an immediate measure, port 427 (SLP) on the external firewall has been closed. Please direct questions about this topic to: cert(at)uni-ulm.de
FB