PetitPotam is an NTLM relay attack, it is a form of manipulator-in-the-middle attack. Microsoft is being vigilant of PetitPotam and its capabilities because malicious actors are using Petitpotam capabilities to attack Windows domain controllers and Windows servers. For protection, Microsoft is releasing many mitigation possibilities to protect customers. To put a stop to NTLM Relay Attacks with NTLM enabled, domain administrators must use Extended Protection for Authentication (EPA) or SMB signing features. PetitPotam is capable of taking dominance on servers where Active Directory Certificate Services ( AD CS ) are not protected for NTLM Relay Attacks.
Use Microsoft Automatic Update to apply the appropriate patch for your system, or the Microsoft Security Update Guide to search for available patches.