CISSP-ISSAP: Information Systems Security Architecture Professional

Dictionary and brute-force attacks attempt to gain unauthorized access by guessing authentication secrets, while spoofing impersonates a trusted identity or service to circumvent authentication. Mail bombing primarily exhausts mailbox, server, or network resources and is therefore a denial-of-service availability attack. NIST SP 800-44 Version 2, NIST SP 800-63B: Threats and Security Considerations