A Distributed Denial-of-Service (DDoS) attack is conducted by sending a high volume of network traffic from various compromised computers and other devices (botnets) to overwhelm a target server, service, or network, with the goal of making the target unavailable to its intended users. Amplified and Reflected attacks are specialized forms of DDoS attacks. On-path attacks involve an attacker intercepting and possibly altering communications between parties without either party's knowledge. Credential replay refers to the unauthorized use of captured user credentials to gain access to systems.