Which type of attack is MOST likely being detected by an Event Viewer message stating, "Special privileges assigned to new login"?

The detection of an Event Viewer message stating "Special privileges assigned to new login" is indicative of a pass-the-hash attack. This type of attack occurs when an attacker captures and uses hashed user credentials to gain unauthorized access to systems, effectively impersonating the legitimate user without needing to know their actual passwords.

In a pass-the-hash attack, when credentials are stored and transmitted in hashed form, attackers can exploit this by obtaining the hash during a system breach or from a network capture. Successful execution of this attack subsequently results in the assignment of special privileges to the attacker's session, which would trigger the Event Viewer alert. This alert serves as a critical indicator that an unauthorized user may have obtained elevated privileges, often leading to further security breaches or access to sensitive data.

The other types of attacks, such as buffer overflow, cross-site scripting, and session replay, do not closely relate to the specific privilege change reflected in the Event Viewer message. Each of these attacks involves different vulnerabilities and techniques that do not typically produce the same event notification concerning privilege assignments. Thus, the event message directly aligns with the characteristics and impacts of a pass-the-hash attack.