A network security analyst monitors the network's IDS, which has flagged unusual activity. The IDS has detected multiple login attempts to a database server within a short period. These attempts come from various IP addresses that are not normally recognized by the network's usual traffic patterns. Each attempt uses the same username and password. Which of the following types of network attacks is most likely occurring?

Cross-site scripting (XSS) involves injecting malicious scripts into trusted websites that are then executed in the browsers of unsuspecting users. This attack primarily targets web applications and user sessions rather than attempting to gain direct access to a server through repeated login attempts using stolen credentials.

A Distributed Denial of Service (DDoS) attack aims to overwhelm a network, system, or service by flooding it with traffic, rendering it unavailable to users. The activity described does not involve traffic overload but instead focuses on unauthorized access attempts, making DDoS an unlikely explanation for the behavior observed.

SQL injection is a technique used to manipulate and execute malicious SQL queries against a database. This type of attack typically targets the database directly through user input fields rather than attempting to authenticate to a system using valid credentials. The login attempts described do not align with the characteristics of an SQL injection attack.