Zerologon

A critical vulnerability was found that allows hackers to take over Windows Domain Controllers using a Netlogon EoP vulnerability that was found mid September.
The vulnerability allows even unskilled hackers to take over a Domain Controller and essentially an entire system. It is recommended that any Windows Domain Controllers be taken OFFLINE and Patched immediately.
Heads up all Microsoft AD administrators! If you are crazy enough to run your servers with direct internet connectivity – you are in *grave* danger. Patch #Zerologon like..last month! https://t.co/sCC2hM0PAj
— Kauto Huopio (@kautoh) September 24, 2020
Internet accessable servers are particularly vulnerable because hackers can take over the system without requiring internal network access making it a very serious threat.