Windows Unusual Count Of Invalid Users Fail To Authenticate Using Kerberos

The following analytic identifies a source endpoint failing to authenticate with multiple invalid domain users using the Kerberos protocol. It leverages Event ID 4768, which is generated when the Key Distribution Center issues a Kerberos Ticket Granting Ticket (TGT) and detects failure code 0x6, indicating the user is not found in the Kerberos database. This behavior is significant as it may indicate a Password Spraying attack, where an adversary attempts to gain initial access or elevate privileges. If confirmed malicious, this activity could lead to unauthorized access and potential privilege escalation within the Active Directory environment.